C Functions Tricky Questions

#include<stdio.h>
int main()
{
	char arr[] = "function\0";
	int num = strlen(a);
	printf("Length of function is  %d", num);
	return 0;	
}

x

 

Option: D

Explanation

Here the char arrray arr will hold the initialized string "function\0", whose length will be counted from 0 till the null character. Hence num holds the integer value 8.

#include<stdio.h>
void abc();
int *ptr;
int main()
{
	int i, *p = &i;
	abc();
	return 0;
}
void  abc()
{
	int i = 0;
	ptr = &i;
	ptr++;
	*ptr = 3;
	printf("\nFunction in C %d", i);
}

x

 

Option: A

Explanation

*ptr = 3 won't affect the value in a variable i. Because ptr is post increment to the next address of i before declaring *ptr = 3.
Thus outputted Function in C 0.

#include<stdio.h>
char normal[15] = "Ambulance";
char accident[15];
int main()
{
	swab(normal, accident, strlen(normal +1));
	printf ("%s\n", normal);
	return 0;
}

x

 

Option: C

Explanation

swab is a special type of function in c, which is capable of swapping two text consecutively in a string.
It must to noted that swab function won't display the last odd charater as we saw here "e" is missing in a string "Ambulance"

#include<stdio.h>
void ptr(char**);
int main()
{
	char *argv[] = { "abc", "def", "ghi", "jkl", "mno", "pqr" };
	ptr(argv);
	return 0;
}
void ptr(char **p)
{
	char *t;
	t = (p += sizeof(int))[-1];
	printf("%s\n", t);
}

x

 

Option: B

Explanation

Here we used pointer array to store a strings ie ) array of string using pointer variable.
ptr() is a valid function which passes the address of first element in an array *argv[].
In ptr() function we get the value p = "abc"
now t = (p = p + sizeof(int))[-1];
t = p = ((address of abc) + 4)[-1]
t = p = (address of mno)[-1]
t = p = address of jkl.
t = jkl as t is single pointer character type

What happens when p is printed

when we printf the value inside p it displays a address as it is a double pointer character type.

#include<stdio.h>
int recursive(int i)
{
	static int count = 0;
	count = count + i;
	return count;
}
int main()
{
	int i, j;
	for (i = 0; i <= 5; i++)
	j = recursive(i);
	printf("%d\n", j);
	return 0;
}

x

 

Option: C

Explanation

static int count = 0 is only for the first time od iteration because its static.

Iteration 1

count = count + i;
count = 0 + 0;
count = 0;

Iteration 2

count = count + 1;
count = 0 + 1;
count = 0;

Iteration 2

count = count + 2;
count = 1 + 2;
count = 3;

Iteration 3

count = count + 3;
count = 3 + 3;
count = 6;

Iteration 4

count = count + 4;
count = 6 + 4;
count = 10;

Iteration 5

count = count + 5;
count = 10 + 5;
count = 15;