Output of C programs | Set 36

1. What will be the output of following?

void main()
{
    int const* p = 5;
    printf("%d", ++(*p));
}

Options:
A. 6
B. 5
C. Garbage Value
D. Compiler Error

Answer : D

Explanation : It will give compile time error because we are trying to change the constant value. p is a pointer to a “constant integer”. But we tried to change the value of the “constant integer”.

2. What will be the output of following?

void main()
{
    char* p;
    printf("%d %d", sizeof(*p), sizeof(p));
}

Options:
A. 1 1
B. 1 8
C. 2 1
D. 2 2

Answer : B

Explanation : The sizeof() operator gives the number of bytes taken by its operand. P is a character pointer, which needs one byte for storing its value (a character). Hence sizeof(*p) gives a value of 1. Since it needs two bytes to store the address of the character pointer sizeof(p) gives 8.

3. What will be the output of following?

void main()
{
    int m, i = 0, j = 1, k = 2;
    m = i++ || j++ || k++;
    printf("%d %d %d %d", m, i, j, k);
}

Options:
A. 1 1 2 3
B. 1 1 2 2
C. 0 1 2 2
D. 0 1 2 3

Answer : B

Explanation : In an expression involving || operator, evaluation takes place from left to right and will be stopped if one of its components evaluates to true(a non zero value).
So in the given expression m = i++ || j++ || k++.
It will be stop at j and assign the current value of j in m.
therefore m = 1, i = 1, j = 2 and k = 2 (since k++ will not encounter. so its value remain 2)

4. What will be the output of following?

void main()
{
    int i = 0;
    printf("%d %d", i, i++);
}

Options:
A. 0 1
B. 1 0
C. 0 0
D. 1 1

Answer : B

Explanation : Since the evaluation is from right to left. So when the print statement execute value of i = 0, as its executing from right to left – when i++ will be execute first and print value 0 (since its post increment ) and after printing 0 value of i become 1.

5. What will be the output of following?

#include <stdio.h>
int main(void)
{
    char p;
    char buf[10] = { 1, 2, 3, 4, 5, 6, 9, 8 };
    p = (buf + 1)[5];
    printf("%d", p);
    return 0;
}

Options:
A. 5
B. 6
C. 9
D. Error

Answer : C

Explanation : x[i] is equivalent to *(x + i), so (buf + 1)[5] is *(buf + 1 + 5), or buf[6].

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