Explore topic-wise MCQs in Engineering.

Is the NULL pointer same as an uninitialised pointer?

Will the program compile in Turbo C?

#include<stdio.h>
int main()
{ int a=10, *j; void *k; j=k=&a; j++; k++; printf("%u %u n", j, k); return 0;
}

Will the following program give any warning on compilation in TurboC (under DOS)?

#include<stdio.h> int main()
{ int *p1, i=25; void *p2; p1=&i; p2=&i; p1=p2; p2=p1; return 0;
}

Which of the following statements correctly declare a function that receives a pointer to pointer to a pointer to a float and returns a pointer to a pointer to a pointer to a pointer to a float?

Which of the following are correct preprocessor directives in C?

Which of the following are correctly formed #define statements in C?

If the file to be included doesn't exist, the preprocessor flashes an error message.

There exists a way to prevent the same file from getting #included twice in the same program.

A preprocessor directive is a message from programmer to the preprocessor.

Is there any difference between the two statements?
char *ch = "IndiaBIX";
char ch[] = "IndiaBIX";

Will the following code work?

#include<stdio.h>
#include<malloc.h> struct emp
{ int len; char name[1];
};
int main()
{ char newname[] = "Rahul"; struct emp *p = (struct emp *) malloc(sizeof(struct emp) -1 + strlen(newname)+1); p->len = strlen(newname); strcpy(p -> name, newname); printf("%d %s n", p->len, p->name); return 0;
}

A pointer union CANNOT be created

For the following statements will arr[3] and ptr[3] fetch the same character?
char arr[] = "IndiaBIX";
char *ptr = "IndiaBIX";

Will the program compile successfully?

#include<stdio.h> int main()
{ char a[] = "India"; char *p = "BIX"; a = "BIX"; p = "India"; printf("%s %s n", a, p); return 0;
}

What will be the output of the program under DOS?

#include<stdio.h> int main()
{ char huge *near *far *ptr1; char near *far *huge *ptr2; char far *huge *near *ptr3; printf("%d, %d, %d n", sizeof(ptr1), sizeof(**ptr2), sizeof(ptr3)); return 0;
}

What will be the output of the program (sample.c) given below if it is executed from the command line (Turbo C in DOS)?
cmd> sample 1 2 3

/* sample.c */
#include<stdio.h> int main(int argc, char *argv[])
{ int j; j = argv[1] + argv[2] + argv[3]; printf("%d", j); return 0;
}

What will be the output of the program?

#include<stdio.h>
#define SQUARE(x) x*x int main()
{ float s=10, u=30, t=2, a; a = 2*(s-u*t)/SQUARE(t); printf("Result = %f", a); return 0;
}

In Turbo C/C++ under DOS if we want that any wild card characters in the command-line arguments should be appropriately expanded, are we required to make any special provision?

On executing the below program what will be the contents of 'target.txt' file if the source file contains a line "To err is human"?

#include<stdio.h> int main()
{ int i, fss; char ch, source[20] = "source.txt", target[20]="target.txt", t; FILE *fs, *ft; fs = fopen(source, "r"); ft = fopen(target, "w"); while(1) { ch=getc(fs); if(ch==EOF) break; else { fseek(fs, 4L, SEEK_CUR); fputc(ch, ft); } } return 0;
}

Bitwise | can be used to multiply a number by powers of 2.

How many bytes of memory will the following code reserve?

#include<stdio.h>
#include<stdlib.h> int main()
{ int *p; p = (int *)malloc(256 * 256); if(p == NULL) printf("Allocation failed"); return 0;
}

Assume integer is 2 bytes wide. What will be the output of the following code?

#include<stdio.h>
#include<stdlib.h>
#define MAXROW 3
#define MAXCOL 4 int main()
{ int (*p)[MAXCOL]; p = (int (*) [MAXCOL])malloc(MAXROW *sizeof(*p)); printf("%d, %d n", sizeof(p), sizeof(*p)); return 0;
}

Preprocessor directive #undef can be used only on a macro that has been #define earlier

What will be the output of the program ?

#include<stdio.h>
#include<string.h> int main()
{ char str1[20] = "Hello", str2[20] = " World"; printf("%s n", strcpy(str2, strcat(str1, str2))); return 0;
}

Which statement will you add to the following program to ensure that the program outputs "IndiaBIX" on execution?

#include<stdio.h> int main()
{ char s[] = "IndiaBIX"; char t[25]; char *ps, *pt; ps = s; pt = t; while(*ps) *pt++ = *ps++; /* Add a statement here */ printf("%s n", t); return 0;
}

What will be the output of the program ?

#include<stdio.h> int main() { char p[] = "%d n"; p[1] = 'c'; printf(p, 65); return 0; } 

What will be the output of the program ?

#include<stdio.h> int main()
{ union var { int a, b; }; union var v; v.a=10; v.b=20; printf("%d n", v.a); return 0;
}

Nested unions are allowed

What will be the output of the program?

#include<stdio.h> int main()
{ unsigned int res; res = (64 >>(2+1-2)) & (~(1<<2)); printf("%d n", res); return 0;
}

Can we have an array of bit fields?

To scan a and b given below, which of the following scanf() statement will you use?

#include<stdio.h> float a;
double b;

What will be the output of the program?

#define P printf("%d n", -1^~0);
#define M(P) int main()  {  P  return 0;  }
M(P)

What will be the output of the program?

#include<stdio.h>
int get(); int main()
{ const int x = get(); printf("%d", x); return 0;
}
int get()
{ return 20;
}

Will the program outputs "IndiaBIX.com"?

#include<stdio.h>
#include<string.h> int main()
{ char str1[] = "IndiaBIX.com"; char str2[20]; strncpy(str2, str1, 8); printf("%s", str2); return 0;
}

Which of the following is the correct usage of conditional operators used in C?

What will be the output of the program?

#include<stdio.h> #include<math.h> int main() { float n=1.54; printf("%f, %f n", ceil(n), floor(n)); return 0; } 

What will be the output of the program?

#include<stdio.h>
int main()
{ float d=2.25; printf("%e,", d); printf("%f,", d); printf("%g,", d); printf("%lf", d); return 0;
}

If a function contains two return statements successively, the compiler will generate warnings. Yes/No ?

What will be the output of the program?

#include<stdio.h>
#include<stdlib.h> int main()
{ union test { int i; float f; char c; }; union test *t; t = (union test *)malloc(sizeof(union test)); t->f = 10.10f; printf("%f", t->f); return 0;
}

Assume integer is 2 bytes wide. How many bytes will be allocated for the following code?

#include<stdio.h> #include<stdlib.h> #define MAXROW 3 #define MAXCOL 4 int main() { int (*p)[MAXCOL]; p = (int (*) [MAXCOL])malloc(MAXROW *sizeof(*p)); return 0; } 

We can allocate a 2-Dimensional array dynamically.

Function can return a floating point number.

malloc() returns a float pointer if memory is allocated for storing float's and a double pointer if memory is allocated for storing double's.

malloc() allocates memory from the heap and not from the stack.

Point out the correct statement which correctly allocates memory dynamically for 2D array following program?

#include<stdio.h>
#include<stdlib.h> int main()
{ int *p, i, j; /* Add statement here */ for(i=0; i<3; i++) { for(j=0; j<4; j++) { p[i*4+j] = i; printf("%d", p[i*4+j]); } } return 0;
}

typedef's have the advantage that they obey scope rules, that is they can be declared local to a function or a block whereas #define's always have a global effect.

Can I increase the size of dynamically allocated array?

Is the following declaration acceptable?

typedef long no, *ptrtono;
no n;
ptrtono p;

malloc() returns a NULL if it fails to allocate the requested memory.

If malloc() successfully allocates memory it returns the number of bytes it has allocated.