Mcq on c

Mcq on C Programming

Q 1 - What is your comment on the below C statement?

   signed int *p=(int*)malloc(sizeof(unsigned int));
A - Improper type casting

B - Would throw Runtime error

C - Memory will be allocated but cannot hold an int value in the memory

D - No issue with statement

Answer : D
Explanation
Option (d), as the size of int and unsigned is same, no problem in allocating memory.

Q 2 - What is the size of the following union definition?

#include<stdio.h>

union abc {
    char a,b,c,d,e,f,g,h;
    int i;
}abc;

main()
{
   printf( "%d", sizeof( abc ));
}
A - 1

B - 2

C - 4

D - 8

Answer : C
Explanation
union size is biggest element size of it. All the elements of the union share common memory.

Q 3 - Identify the invalid constant used in fseek() function as ‘whence’ reference.

A - SEEK_SET

B - SEEK_CUR

C - SEEK_BEG

D - SEEK_END

Answer : C
Explanation
SEEK_BEG, all the rest are valid constants defined in ‘stdio.h’

Q 4 - Choose the invalid predefined macro as per ANSI C.

A - __FILE__

B - __DATE__

C - __TIME__

D - __C++__

Answer : D
Explanation
There is no macro define with the name __C++__, but __cplusplus is defined by ANSI)

Q 5 - What is the built in library function to compare two strings?

A - string_cmp()

B - strcmp()

C - equals()

D - str_compare()

Answer : B
Explanation
strcmp() is the built in function from “string.h” to compare two strings. Returns 0 if both are same strings. Returns -1 if first < second string. Returns 1 first > second.

Q 6 - The C library function rewind() reposition the file pointer at the beginning of the file.

A - True

B - False

Answer : A
Explanation
void rewind(FILE *stream): In C, the rewind function reposition the file position to the beginning of the file of the given stream. It also erases the error and end-of-file indicators for stream.

Q 7 - Similarity between a structure, union and enumeration,

A - All are helpful in defining new variables

B - All are helpful in defining new data types

C - All are helpful in defining new pointers

D - All are helpful in defining new structures

Answer : B
Explanation
A structure, union and enumeration all of them can define a new data type.

Q 8 - In the given below code, the P2 is

   Typedef int *ptr;

   ptr p1, p2;
A - Integer

B - Integer pointer

C - Both, Integer & Integer pointer

D - None of above

Answer : B
Explanation
Ptr is an alias to int*.

Q 9 - What will be the resultant of the given below program?

#include<stdio.h>
#include<stdarg.h>

Void fun(char *msg, ...);
int main ()
{
   fun("IndiaMAX", 1, 4, 7, 11, 0);
   return 0;
}
   void fun(char *msg, ...)
{
va_list ptr;{
   int num;
   va_start(ptr, msg);
   num = va_arg(ptr, int);
   num = va_arg(ptr, int);
   printf("%d", num);
}
A - IndiaMAX 1, 7, 11, 0

B - IndiaMAX 1, 7

C - Only 4

D - 1, 7, 11, 0

Q 10 - What will be the output of the given below code?

#include<stdio.h>

int main()
{
   const int *ptr = &i;

   char str[] = "Welcome";
   s = str;
   while(*s)
   printf("%c", *s++);
   return 0;
}
A - Welcome

B - 0

C - Wel

D - Come

Answer : A
Explanation
Although, char str[] = "Welcome"; and s = str;, the program will print the value of s.

#include<stdio.h>

int main()
{
   const int *ptr = &i;

   char str[] = "Welcome";
   s = str;
   while(*s)
   printf("%c", *s++);
   return 0;

}