C Questions only (1)
1.
Sample Code
#include
int main(void) {
{int i=10; goto lbl;}
{int i=20; {int i=30; lbl:;}
printf("%i", ++i);}
}
Refer to the above sample code. What does this program print?
1 10
2 11
3 21
4 31
5 An undefined value
2.
short testarray[4][3] = { {1}, {2, 3}, {4, 5, 6} };
printf( "%d\n", sizeof( testarray ) );
Assuming a short is two bytes long, what will be printed by the above code?
1 It will not compile because not enough initializers are given.
2 6
3 7
4 12
5 24
3.
Which of the following choices most accurately describes variable DEFINITION (as opposed to declaration)?
1 The assignment of properties and storage space to a variable
2 The identification of a variable that resides elsewhere in the program
3 The assignment of storage space to a variable
4 The assignment of properties to a variable
5 The assignment of storage space to a variable whose
properties have been specified external to the current file scope
4.
How do you include a system header file called
sysheader.h in a C source file?
1 #includefile
2 #include sysheader.h
3 #incl "sysheader.h"
4 #include
5 #incl
5.
Sample Code
f = fopen( fileName, "r" );
From the sample above, which one of the following statements will set the file position for the file f to cause the next byte read from the file to be the last byte?
1 f = feof( f ) - 1;
2 fsetpos( f, EOF - 1 );
3 fseek( f, -1, SEEK_SET );
4 fseek( f, -1, EOF );
5 fseek( f, -1, SEEK_END );
6.
/* Initialize an array with zero values. */
void bzero (void * b, size_t len) {
char *buf = b;
int i;
for (i = 0; i <= len; i++)
*(buf + i) = 0;
}
The function bzero(), defined above, contains a common programming error.
Which one of the following correctly describes it?
1 The loop writes beyond the end of buf.
2 buf refers to an array and should be indexed as one; the pointer
notation applied by the loop causes the wrong address to be
dereferenced.
3 It is not permitted to declare objects of type size_t; this type
is reserved for exclusive usage by the standard library's internal
routines.
4 A generic pointer cannot be cast to a pointer of a more specific type.
5 The comparison between int i and size_t len is not permitted by Standard C.
7.
Sample Code
long factorial (long x)
{
return x * factorial(x - 1);
}
What will the function above return if called with x equal to 5?
1 0
2 15
3 120
4 The program will not compile.
5 The function will never return.
8.
Which one of the following describes a C character string?
1 A sequence of char objects in EBCDIC format
2 A sequence of printable ASCII characters
3 Any pointer to type char
4 An array of bytes terminated by NUL
5 A sequence of char objects in ASCII format
9.
#include %lt;stdlib.h>
int f(TYPE x) {
/*Allocates an array of two integers; returns 0
if the allocation succeeded, 1 otherwise.
Returns the allocated array in x.
*/
int *ret = (int*)malloc(sizeof(int[2]));
return ret ? *x=ret, 0 : 1;
}
Referring to the sample code above, how should TYPE be declared?
1 typedef int**TYPE;
2 typedef int*TYPE;
3 typedef int[]TYPE;
4 typedef &(int*)TYPE;
5 typedef int[]*TYPE;
10.
Which one of the following is a valid variable name?
1 Account_Number
2 Account Number
3 "Account Number"
4 Account^Number
5 Account-Number
C Questions only (2)
11.
/* fp points to an open stream.
* Process a full stream of binary data. */
unsigned long process_binary_data(FILE *fp) {
char ch;
unsigned long count = 0UL;
assert(fp != NULL);
while ((ch = fgetc(fp)) != EOF) {
process_byte(ch);
count++;
}
return count;
}
The function process_binary_data(), defined above, may fail to process the entire stream under exceptional conditions. Which one of the following explains this error?
1 The disparity between the type of ch and the type of EOF causes the loop to execute forever.
2 The loop may fail to process the entire stream underlying fp because it does not check for errors.
3 It is incorrect to use the assignment operator in a loop condition. The programmer probably meant to use the equality operator.
4 The function body contains incorrectly nested parentheses.
5 count fails to contain the number of bytes actually processed.
12.
int x = 3;
if( x == 2 ); x = 0;
if( x == 3 ) x++;
else x += 2;
What value will x contain when the sample code above is executed?
1 1
2 2
3 3
4 4
5 5
13.
int x[] = {1, 2, 3, 4, 5};
int *ptr, **ptr2;
ptr = x;
ptr2 = &ptr;
Referring to the sample code above, how do you update x[2] to 10 using ptr2?
1 (**ptr2 + 2) = 10;
2 **(ptr2 + 2) = 10;
3 *(*ptr2 + 2) = 10;
4 *(&ptr2 + 2) = 10;
5 **(*ptr2 + 2) = 10;
14.
Which one of the following declarations ensures that ptr CANNOT be used to modify the string to which it points (although ptr itself may be changed to point to another string)?
1 static char *ptr = "Hello";
2 const char *ptr = "Hello";
3 char *ptr = const "Hello";
4 char * static ptr = "Hello";
5 char * const ptr = "Hello";
15.
int a [25];
int * p = a + 3;
Which one of the following is functionally equivalent to the code fragment above?
1 int a [25];
int * p = &a[3];
2 int a [25];
int * p = &(a + 3);
3 int a [25];
int * p = &a[2];
4 int a [25];
int * p = (&a)[3];
5 int a [25];
int * p = a[3];
16.
Which one of the following code fragments causes k to contain the value 16 at some point?
1 int j = 14;
int k = 1;
k += j+;
2 int k;
**((int **) &k) = 16;
3 int j;
int k = 4;
j = k << 10;
k <<= j >> 11;
k += j;
4 int j, k;
j = 2 << 3;
k = j & 47;
5 int j = 256;
int k = 14;
k = j % k;
k += 2;
17.
Sample Code
#define X(t,m) (size_t)((char*)&((t*)0)->m-(char*)(t*)0)
Consider the poorly named macro X(), defined above. Of which one of the following Standard C macros could X() be an implementation?
1 va_start()
2 putchar()
3 va_arg()
4 offsetof()
5 feof_unlocked()
18.
For which one of the following reasons did the writers of MS-DOS C compilers augment C by adding the reserved words __near, __far, and __huge?
1 They are reserved for usage by compiler writers and have no relevance to other programmers, hence the leading pair of underscores.
2 They indicate that the compiler should place objects in the data segment, on the stack, and on the heap, respectively.
3 They are specific to x86 architecture, and allow the programmer to override the default memory model for specific objects.
4 They allow the compiler to perform additional code optimizations on pointer values.
5 They indicate that an object should be placed near the lowest address, near the highest address, and that an object requires multiple pages, respectively.
19.
Sample Code
extern void *ptr1;
extern void *ptr2;
int compare( int n )
{
return ????;
}
What should replace the ???? in the code above to compare the first n bytes of the memory pointed to by ptr1 and ptr2 and return a non-zero value if they are equal?
1 memcmp( ptr1, ptr2, n )
2 !memcmp( ptr1, ptr2, n )
3 !strncmp( ptr1, ptr2, n )
4 memncmp( ptr1, ptr2, n )
5 strncmp( ptr1, ptr2, n )
C Questions only (3)
20.
Sample Code
void memset (void * buf, int c, size_t len) ??<
unsigned char * b;
register int i;
assert(buf);
debug("assert(buf) => TRUE??/n");
b = buf;
for (i = 0; i < len; i++) ??<
b??(i??) = c;
debug("b??(i??) <- c??/n");
??>
??>
Consider the function memset(), defined above. Which one of the following is a completely true statement about the code shown above?
1 Some accesses performed on b are out-of-bounds.
2 Providing that debug() is declared and correctly used, the code compiles correctly under a Standard C compiler.
3 The three-character sequences starting with ?? were inserted by Microsoft Word.
4 The source code file containing memset() has probably become corrupted. This code clearly does not compile.
5 Assuming that debug() prints its string argument, the strings will run together on the same line.
21.
Which one of the following is the result type of the sizeof operator?
1 unsigned char
2 int
3 char
4 unsigned int
5 size_t
22.
Which one of the following best describes the Standard C convention regarding variables with names that start with an underscore (_)?
1 They are reserved for usage by standards committees, system implementers, and compiler engineers.
2 They are deprecated by Standard C and are permitted only for backward compatibility with older C libraries.
3 Applications programmers are encouraged to employ them in their own code in order to mark certain symbols for internal usage.
4 They are case-insensitive.
5 They are generally treated differently by preprocessors and compilers from other identifiers.
23.
Sample Code
int i,j;
int ctr = 0;
int myArray[2][3];
for (i=0; i<; i++)
for (j=0; j<2; j++)
{
myArray[j][i] = ctr;
++ctr;
}
What is the value of myArray[1][2]; in the sample code above?
1 1
2 2
3 3
4 4
5 5
24.
Sample Code
int i = 4;
switch (i)
{
default:
;
case 3:
i += 5;
if ( i == 8)
{
i++;
if (i == 9) break;
i *= 2;
}
i -= 4;
break;
case 8:
i += 5;
break;
}
printf("i = %d\n", i);
What will the output of the sample code above be?
1 i = 5
2 i = 8
3 i = 9
4 i = 10
5 i = 18
25.
Which one of the following functions returns the string representation from a pointer to a time_t value?
1 localtime
2 gmtime
3 ctime
4 strtime
5 asctime
26.
Which one of the following is a true statement about an lvalue?
1 An lvalue is the result of an arithmetic operation involving quantities of type long int.
2 All lvalues can be used on the right side of an assignment statement.
3 An lvalue is, by definition, the value appearing on the rightmost side of an assignment
statement.
4 By definition, an lvalue is the storage space indirectly referenced by a pointer.
5 An lvalue is any quantity capable of appearing on the left side of a shift operator.
27.
Which one of the following is a true statement about non-generic (void *) pointers?
1 For efficiency, pointer values are always stored in machine registers.
2 A pointer to one type may not be cast to a pointer to any other type.
3 Similarly typed pointers may be subtracted from each other.
4 They are always 32-bit values.
5 Similarly typed pointers may be added to each other.
28.
Which one of the following will read a character from the keyboard and will store it in the variable c?
1 c = getchar();
2 c = getchar( stdin );
3 getchar( &c )
4 getc( &c );
5 c = getc();
29.
Which one of the following is NOT a valid statement?
1 ++d+++e++;
2 f*=g+=h=5;
3 l-->>m<<--n;
4 int a(int a),b=0,c=a((c=b,++b));
5 i->j<-k;
30.
int factorial (int x) {
extern jmp_buf jb;
int fact, chk;
if (!x) return 1;
fact = x * (chk = factorial(x - 1));
if (chk > fact) longjmp(jb, -1);
return fact;
}
int check_for_overflow (int x) {
extern jmp_buf jb;
if (setjmp(jb)) {
printf("discovered overflow in factorial(%d)\n", x);
return 0;
}
if (x < 0) x = 0;
return factorial(x);
}
There is an error in check_for_overflow that may occasionally result in unexpected values in var jb. Which one of the following describes this error?
1 longjmp() cannot safely be used to escape from a recursive call chain.
2 The argument to check_for_overflow() should be qualified with volatile to ensure correct
error reporting.
3 setjmp() and longjmp() must be invoked within the same stack frame. The result of longjmp()
in this case is undefined.
4 The calls to setjmp() and longjmp() operate on different jump buffers, and therefore may
have an undefined effect.
5 The factorial of zero (0) is incorrectly handled by factorial().
C Questions only (4)
31.
The mostly redundant reserved word auto signifies that the compiler should allocate
storage for a variable ___________.
Which one of the following correctly completes the statement above?
1 Only on the stack
2 Only in a register
3 Only until the end of the block
4 Only in the data segment
5 Only on the heap
32.
Which of the following correctly enumerate predefined streams?
1 stddev, stdprn, and stdmon
2 stdin, stdout, and stderr
3 stdin, stdout, and stdterm
4 stdio and stderr
5 stdin, stdlib, and stderr
33.
Which one of the following Standard C functions can be used to sort a string array?
1 qsort
2 sort
3 quicksort
4 asort
5 There is no Standard C function for such a sort.
34.
An expression consisting solely of literals can appear anywhere that literals of the same type can appear.
Which one of the following correctly assesses the statement above?
1 The statement is true.
2 The statement is false. A constant expression may contain side effects that prevent it from
being evaluated at compile time. Since it cannot be universally permitted, it is universally
prohibited.
3 The statement is false. While a constant expression could logically appear wherever a
literal could appear, the Standard C committee chose to allow constant expressions only in
runtime contexts.
4 The statement is false. A constant expression cannot appear as the operand of sizeof or in
the size definition of an array.
5 The statement is false. To simplify the design of the compiler, C compiler implementers are
not obliged to evaluate constant expressions at compile time.
35.
/* sys/cdef.h */
#if defined(__STDC__) || defined(__cplusplus)
#define __P(protos) protos
#else
#define __P(protos) ()
#endif
/* stdio.h */
#include
div_t div __P((int, int));
The code above comes from header files for the FreeBSD implementation of the C library. What is the primary purpose of the __P() macro?
1 The __P() macro provides backward compatibility for K&R C compilers, which do not recognize
Standard C prototypes.
2 The __P() macro has no function, and merely obfuscates library function declarations.
It should be removed from further releases of the C library.
3 The __P() macro provides forward compatibility for C++ compilers, which do not recognize
Standard C prototypes.
4 Identifiers that begin with two underscores are reserved for C library implementations.
It is impossible to determine the purpose of the macro from the context given.
5 The __P() macro serves primarily to differentiate library functions from
application-specific functions.
36.
Sample Code
int aFunction(int y)
{
int x = 3 * y;
return x;
}
In the sample code above, with what scope is the variable x implicitly declared?
1 extern
2 static
3 auto
4 volatile
5 register
37.
Which one of the following statements regarding macros is INCORRECT?
1 Macro definitions can contain expressions.
2 Macro definitions cannot be altered at runtime.
3 Macros can have parameters.
4 Macros are evaluated in the preprocessor.
5 Macros are evaluated at runtime.
38.
Sample Code
void listFile( FILE *f )
{
int c;
while( c = fgetc( f ) != EOF )
{
printf( "%d", c );
}
printf( "\n" );
}
What will be printed when the function above is called with a pointer to an open file that contains the three characters abc?
1 111
2 000
3 656667
4 abc
5 The characters ab followed by an infinite number of c's
39.
Which one of the following will turn off buffering for stdout?
1 setbuf( stdout, NULL );
2 setbuf( stdout, FALSE );
3 setvbuf( stdout, NULL );
4 setbuf( stdout, _IONBF );
5 setvbuf( stdout, _IONBF );
C Questions only (5)C Questions only (6)
49.
Sample Code
int my_func( int *a );
int main()
{
int b[3];
my_func( ???? );
return 0;
}
Referring to the sample code above, which one of the following must be inserted in place of the ???? to pass the array b to my_func?
1 (int *)b[0]
2 b
3 (int *)*b
4 (*b)[0]
5 *b
50.
Sample Code
void printTime( time_t *t )
{
????
}
Which one of the following can replace the ???? in the code above to print the time passed in t in human-readable form?
1 char s[ 100 ];
ctime( t, s );
printf( "%s\n", s );
2 printf( "%s\n", ctime( t ) );
3 printf( "%s\n", asctime( t ) );
4 printf( "%s", t );
5 char *s = ctime( t );
printf( "%s\n", s );
free( s );
51.
How do you declare a constant pointer to a constant string?
1 const* char const p;
2 const const char* p;
3 char const const* p;
4 const char const* p;
5 const char* const p;
52.
Sample Code #include
int ab=1;
int a=2;
int main(){
int b=3;
int ab=4;
printf("%i/*%i*/%i",a,b,ab);
}
Refer to the above sample code. What will be printed?
1 21
2 0/*4*/1
3 01
4 %i/*%i*/%i041
5 2/*3*/4
53.
Sample Code
int z;
int x = 5;
int y = -10;
int a = 4;
int b = 2;
z = x++ + ++y * b / a;
What number will z in the sample code above contain?
1 -3
2 -2
3 0
4 1
5 2
54.
Which one of the following functions allows an existing stream to be redirected?
1 setvbuf()
2 dup()
3 fopen()
4 popen()
5 freopen()
55.
Sample Code
int x = 0;
for ( ; ; )
{
if (x++ == 4) break;
continue;
}
printf("x=%d\n", x);
What will be printed when the sample code above is executed?
1 x=0
2 x=1
3 x=4
4 x=5
5 x=6
56.
Sample Code
/* Eliminate all whitespace from the end of s. */
void rtrim (char * s) {
char * start, ws, text;
start = s, ws = text = s - 1;
while (*s != '\0') {
if (isspace(*s)) {
ws = s;
while (isspace(*s)) s++;
} else {
text = s;
while (*s != '\0' && !isspace(*s)) s++;
}
}
if (ws > text) *ws = '\0';
}
The function rtrim(), defined above, contains an implementation error. Which one of the following describes it?
1 The comma operator has a higher precedence than assignment; this produces an unintended effect.
2 rtrim() does not correctly handle the case where no character of s is whitespace.
3 rtrim() does not correctly handle the case where every character of s is whitespace.
4 ws and text are not assignment-compatible with s or NULL.
5 The loop and its subordinate statements do not adequately detect an end-of-string condition on s in all cases.
57.
Sample Code
struct customer *ptr = malloc( sizeof( struct customer ) );
Given the sample allocation for the pointer "ptr" found above, which one of the following statements is used to reallocate ptr to be an array of 10 elements?
1 ptr = realloc( ptr, 10 * sizeof( struct customer ) );
2 realloc( ptr, 10 * sizeof( struct customer ) );
3 realloc( ptr, 9 * sizeof( struct customer ) );
4 ptr += malloc( 9 * sizeof( struct customer ) );
5 ptr = realloc( ptr, 9 * sizeof( struct customer ) );
C Questions only (7)
58.
Sample Code
struct node {
int id;
int length;
struct node * next;
struct node * prev;
unsigned char data [1];
}
Consider struct node, an aggregate type defined above. Which one of the following might explain the declaration of its peculiar member data?
1 There is no difference between character unsigned char data and array unsigned char data [1], since each allocates only a single byte. Identical operations can be performed on both quantities. The choice was one of preference.
2 The programmer is declaring a bit field called data, which consists of only a single bit. struct node probably represents some hardware device.
3 data is probably used in conjunction with length and malloc() to create objects of variable size. struct node is essentially a header for an object of indeterminate size.
4 The information provided by the definition of struct node is insufficient to formulate a guess about the purpose of the member data or its strange declaration.
5 Clearly the programmer has made a typo. If the programmer had intended to allocate only a single byte, he or she would have declared data as unsigned char data instead.
59.
Sample Code
char ca[]="abc\012\0x34";
Refer to the above sample code. What does strlen(ca) return, using a Standard C compiler?
1 3
2 4
3 5
4 10
5 12
60.
sizeof(L"Hello world!") == x
Consider the code fragment above. For which value of x is the expression above true?
1 sizeof(char *)
2 sizeof(wchar_t [])
3 12
4 13
5 13 * sizeof(wchar_t);
61.
unsigned i, *ip = &i;
*ip = *ip & ~*ip;
What does the above sample code do?
1 It sets ip to 0.
2 It sets all the bits of i to 0.
3 It sets i to the value of UINT_MAX.
4 It sets ip to NULL.
5 It produces an undefined result.
62.
Sample Code
char*(*(*x)(void))[];
What does the above statement declare?
1 An array of pointers to a function with no parameters returning a pointer to a string pointer
2 An array of pointers to a pointer to a function with no parameters returning a string
3 A pointer to an array of functions with no parameters returning a string
4 A pointer to a function with no parameters that returns a pointer to an array of strings
5 It is a syntactically incorrect statement.
63.
#include
#include
void f(int x) {
char b[] = "1234567";
strncpy(b, "abc", x);
{
int i=0;
for(; i
}
}
int main() {
f(2); f(6);
return 0;
}
What does the above program print?
1 ab34567abc4567
2 ab*4567*abc***7*
3 ab34567*abc***7*
4 ab*4567abc***7
5 ab*4567*abc*567*
64.
Sample Code
char c = '\101';
What will the variable c contain in the code above?
1 It will not compile.
2 The four characters '\', '1', '0', '1'
3 A backslash '\'.
4 65 (which is the letter A in ASCII)
5 101 (which is the letter e in ASCII)
65.
Sample Code
void myFunc (int x)
{
if (x > 0) myFunc(--x);
printf("%d, ", x);
}
int main()
{
myFunc(5);
return 0;
}
What will the above sample code produce when executed?
1 5, 4, 3, 2, 1, 0,
2 0, 0, 1, 2, 3, 4,
3 4, 3, 2, 1, 0, 0,
4 1, 2, 3, 4, 5, 5,
5 0, 1, 2, 3, 4, 5,
66.
Sample Code
char s1[100];
char s2[100];
gets( s1 );
fgets( s2, sizeof(s2), stdin);
printf( "%d\n", strlen( s1 ) - strlen( s2 ) );
What will be printed when the above code is executed and the string "abcd" is entered twice on stdin?
1 -1
2 0
3 1
4 2
5 4
C Questions only (8)
67.
Which one of the following correctly declares a pointer to an array of 12 characters?
1 char (* a) [12];
2 char (* a) [11];
3 char * a [11];
4 char * (a [12]);
5 char * (a [11]);
68.
Sample Code
void zero_array (char a [20]) {
size_t size;
assert(a);
size = sizeof(a);
memset(a, 0, size);
}
The function zero_array(), defined above, contains an error. Which one of the following describes it?
1 The result of sizeof(a) may be subject to a type cast that causes size to acquire an erroneous value. The call to memset() will probably clear the wrong number of bytes.
2 The assert() macro may incorrectly cause the code to abort if the host machine uses a constant other than zero (0) to represent the null pointer natively.
3 Standard C does not permit programmers to declare the size of the leftmost dimension of an array parameter. The compiler should print an error when parsing zero_array().
4 sizeof(a) evaluates to sizeof(char *) rather than twenty (20). The call to memset() will probably clear the wrong number of bytes.
5 The second and third arguments to memset() are probably reversed.
69.
Sample Code
time_t currentTime = time( NULL );
printf("%s\n", ???? );
Which one of the following can replace ???? in order for the above sample code to print out the current time as a human-readable string?
1 ctime(¤tTime)
2 asctime(¤tTime)
3 asctime(currentTime)
4 timestr(currentTime)
5 strtime(currentTime)
70.
Sample Code
#include
static double (*funcs[])( double ) =
{
sin, cos, tan, asin, acos, atan, sinh, cosh, tanh
};
double computeTrigFunction( int index, double argument )
{
return ????;
}
Referring to the sample code above that should compute the value of a trigonometric function based on its index, what would be a replacement for the ???? to make the correct call?
1 *funcs[ index ]( argument )
2 (*funcs)[ index ]( argument )
3 funcs(argument)[index]
4 *(funcs[index](argument))
5 funcs[index](argument)
71.
Sample Code
file inc.h contains only the following line:
struct x {int d; char c;}
file main.c contains only the three following lines:
#include
#include "inc.h"
main(int n, char**a) { exit(0); }
Refer to the above sample code. The program is supposed to be Standard C. What is the problem with main in this code?
1 main does not return a value.
2 The parameters of main must be named argc and argv.
3 main is missing a return type.
4 The parameters of main are not used.
5 The type of the second parameter of main is invalid.
72.
Sample Code
int x = 5;
int y = 2;
char op = '*';
switch (op)
{
default : x += 1;
case '+' : x += y;
case '-' : x -= y;
}
After the sample code above has been executed, what value will the variable x contain?
1 4
2 5
3 6
4 7
5 8
1.
class A {
};
class B {
protected:
friend class A;
};
class C {
public:
friend class B;
};
Referring to the sample code above, assuming the above classes had data members, what names of C's members could be used in declarations of members of A?
1) Only private members
2) Only protected members
3) All of C's data members
4) Only public members
5) None of C's data members
C Questions only (9)
1. What does static variable mean?
2. What is a pointer?
3. What is a structure?
4. What are the differences between structures and arrays?
5. In header files whether functions are declared or defined?
6. What are the differences between malloc() and calloc()?
7. What are macros? What are the advantages and disadvantages?
8. Difference between pass by reference and pass by value?
9. What is static identifier?
10. Where are the auto variables stored?
11. Where does global, static, local, register variables, free memory and C Program instructions get stored?
12. Difference between arrays and linked list?
13. What are enumerations?
14. Describe about storage allocation and scope of global, extern, static, local and register variables?
15. What are register variables? What are the advantage of using register variables?
16. What is the use of typedef?
17. Can we specify variable field width in a scanf() format string? If possible how?
18. Out of fgets() and gets() which function is safe to use and why?
19. Difference between strdup and strcpy?
20. What is recursion?
21. Differentiate between a for loop and a while loop? What are it uses?
22. What are the different storage classes in C? 23. Write down the equivalent pointer expression for referring the same element a[i][j][k][l]?
24. What is difference between Structure and Unions?
25. What the advantages of using Unions?
26. What are the advantages of using pointers in a program?
27. What is the difference between Strings and Arrays?
28. In a header file whether functions are declared or defined?
29. What is a far pointer? where we use it?
30. How will you declare an array of three function pointers where each function receives two ints and returns a float?
31. What is a NULL Pointer? Whether it is same as an uninitialized pointer?
32. What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?
33. What does the error ‘Null Pointer Assignment’ mean and what causes this error?
34. What is near, far and huge pointers? How many bytes are occupied by them?
35. How would you obtain segment and offset addresses from a far address of a memory location?
36. Are the expressions arr and *arr same for an array of integers?
37. Does mentioning the array name gives the base address in all the contexts?
38. Explain one method to process an entire string as one unit?
39. What is the similarity between a Structure, Union and enumeration?
40. Can a Structure contain a Pointer to itself?
41. How can we check whether the contents of two structure variables are same or not?
42. How are Structure passing and returning implemented by the complier?
43. How can we read/write Structures from/to data files?
44. What is the difference between an enumeration and a set of pre-processor # defines?
45. What do the ‘c’ and ‘v’ in argc and argv stand for?
46. Are the variables argc and argv are local to main?
47. What is the maximum combined length of command line arguments including the space between adjacent arguments?
48. If we want that any wildcard characters in the command line arguments should be appropriately expanded, are we required to make any special provision? If yes, which?
49. Does there exist any way to make the command line arguments available to other functions without passing them as arguments to the function?
50. What are bit fields? What is the use of bit fields in a Structure declaration?
51. To which numbering system can the binary number 1101100100111100 be easily converted to?
52. Which bit wise operator is suitable for checking whether a particular bit is on or off?
53. Which bit wise operator is suitable for turning off a particular bit in a number?
54. Which bit wise operator is suitable for putting on a particular bit in a number?
55. Which bit wise operator is suitable for checking whether a particular bit is on or off?
56. Which one is equivalent to multiplying by 2?
* Left shifting a number by 1
* Left shifting an unsigned int or char by 1?
57. Write a program to compare two strings without using the strcmp() function.
58. Write a program to concatenate two strings.
59. Write a program to interchange 2 variables without using the third one.
60. Write programs for String Reversal. The same for Palindrome check.
61. Write a program to find the Factorial of a number.
62. Write a program to generate the Fibonacci Series?
63. Write a program which employs Recursion?
64. Write a program which uses command line arguments.
65. Write a program which uses functions like strcmp(), strcpy(), etc.
66. What are the advantages of using typedef in a program?
67. How would you dynamically allocate a one-dimensional and two-dimensional array of integers?
68. How can you increase the size of a dynamically allocated array?
69. How can you increase the size of a statically allocated array?
70. When reallocating memory if any other pointers point into the same piece of memory do you have to readjust these other pointers or do they get readjusted automatically?
71. Which function should be used to free the memory allocated by calloc()?
72. How much maximum can you allocate in a single call to malloc()?
73. Can you dynamically allocate arrays in expanded memory?
74. What is object file? How can you access object file?
75. Which header file should you include if you are to develop a function which can accept variable number of arguments?
76. Can you write a function similar to printf()?
77. How can a called function determine the number of arguments that have been passed to it?
78. Can there be at least some solution to determine the number of arguments passed to a variable argument list function?
79. How do you declare the following:
* An array of three pointers to chars
* An array of three char pointers
* A pointer to array of three chars
* A pointer to function which receives an int pointer and returns a float pointer
* A pointer to a function which receives nothing and returns nothing
80. What do the functions atoi(), itoa() and gcvt() do?
81. Does there exist any other function which can be used to convert an integer or a float to a string?
82. How would you use qsort() function to sort an array of structures?
83. How would you use qsort() function to sort the name stored in an array of pointers to string?
84. How would you use bsearch() function to search a name stored in array of pointers to string?
85. How would you use the functions sin(), pow(), sqrt()?
86. How would you use the functions memcpy(), memset(), memmove()?
87. How would you use the functions fseek(), freed(), fwrite() and ftell()?
88. How would you obtain the current time and difference between two times?
89. How would you use the functions randomize() and random()?
90. How would you implement a substr() function that extracts a sub string from a given string?
91. What is the difference between the functions rand(), random(), srand() and randomize()?
92. What is the difference between the functions memmove() and memcpy()?
93. How do you print a string on the printer?
94. Can you use the function fprintf() to display the output on the screen?
95. Gautam Pagedar adds this question: What is a linklist and why do we use it when we have arrays? - I feel the correct answer should be linklist is used in cases where you don’t know the memory required to store a data structure and need to allocate is dynamically on demand.
96. How do you detect a loop in linked list?
97. Sunil asks: What is the difference between main() in C and main() in C++?
98. ajz at his interviews asks what will be printed out when the following code is executed:
main()
{ printf("%x",-1<<4);
}
99. What will happen in these three cases?
if(a=0){
//somecode
}
if (a==0){
//do something
}
if (a===0){
//do something
}
Sample Code
char buf[ 50 ] = "Hello World";
char *ptr = buf + 5;
From the sample above, what is the proper way to copy 20 bytes from the location pointed to by ptr to the beginning of buf?
1 memcpy( buf, ptr, 20 );
2 It cannot be done because the source and destination overlap.
3 strncpy( buf, ptr, 20 );
4 That may cause an illegal memory access because it will read memory past the end of the string.
5 memmove( buf, ptr, 20 );
41.
Which one of the following will declare a pointer to an integer at address 0x200 in memory?
1 int *x = &0x200;
2 int *x = *0x200;
3 int *x( &0x200 );
4 int *x;
*x = 0x200;
5 int *x = 0x200;
42.
int *x;
x = (int *) 15;
Is the above code legal?
1 Yes; upon initialization, the number 15 is stored in a special pointer memory address space.
2 Yes; a new memory space is allocated to hold the number 15.
3 No; this syntax is not allowed.
4 Yes; the pointer x points at the integer in memory location 15.
5 No; this assigns the number 15 to an unallocated space in memory.
43.
x[2] = 5 vs.
2[x] = 5
Are x[2] and 2[x] identical in the sample code above? Why or why not?
1 Yes; both are identical because they are resolved to pointer references.
2 Yes; both are identical because the compiler will identify the x variable and make adjustments.
3 No; x[2] is correct, but 2[x] is invalid syntax.
4 No; both variable assignments have invalid syntax.
5 No; 2[x] is correct, but x[2] is invalid syntax.
44.
Sample Code
int x=1;
int y=x+++ ++x;
Refer to the above sample code. What is the value of y?
1 2
2 3
3 4
4 5
5 The value is implementation dependent because it is not defined in Standard C.
45.
Which one of the following functions is the Standard C functional equivalent of the AT&T Unix function rindex(), which returns a pointer to the last occurrence of a character in a string or NULL if no such character exists?
1 strrchr()
2 stridx()
3 strcspn()
4 strchr()
5 strridx()
46.
Which one of the following declarations ensures that ptr CANNOT be used to modify the string to which it points (although ptr itself may be changed to point to another string)?
1 const char *ptr = "Hello";
2 char *ptr = const "Hello";
3 char * static ptr = "Hello";
4 static char *ptr = "Hello";
5 char * const ptr = "Hello";
47.
Sample Code
char * strdup (const char * s) {
char * buf;
int len;
assert(s != NULL);
len = strlen(s);
buf = (char *) calloc(len + 1, sizeof(char));
memcpy(buf, s, len);
return buf;
}
The proposed implementation of strdup() above contains a runtime error that may NOT appear consistently with each invocation. Which one of the following accurately describes this error?
1 The arguments to calloc() do not cause enough memory to be allocated for storing the contents of s.
2 If memory is scarce, calloc() may fail and return NULL. The code does not anticipate this condition.
3 memcpy() may corrupt data if used to copy ASCII strings.
4 buf is never NUL-terminated, and therefore cannot be used by C library functions affecting strings.
5 The function returns a pointer to dynamic memory. This practice should be avoided and always constitutes a memory leak.
48.
Sample Code
int a[5] = {1, 2, 3, 4, 5};
int *aPtr;
aPtr = a;
printf("element=%d\n", *(aPtr + 2));
What will be printed when the sample code above is executed?
1 element=1
2 element=2
3 element=3
4 element=4
5 element=5
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