Declarations And Initializations

What is the output of the program?

#include<stdio.h>
int main()
{
    union a
    {
        int i;
        char ch[2];
    };
    union a u;
    u.ch[0] = 3;
    u.ch[1] = 2;
    printf("%d, %d, %d\n", u.ch[0], u.ch[1], u.i);
    return 0;
}

A:

3, 2, 515

B:

515, 2, 3

C:

3, 2, 5

D:

None of these

Answer: A

printf("%d, %d, %d\n", u.ch[0], u.ch[1], u.i); It prints the value of u.ch[0] = 3, u.ch[1] = 2 and it prints the value of u.i means the value of entire union size.

So the output is 3, 2, 515.

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What is the output of the program

#include<stdio.h>
int main()
{
    int a[5] = {2, 3};
    printf("%d, %d, %d\n", a[2], a[3], a[4]);
    return 0;
}

A:

Garbage Values

B:

2, 3, 3

C:

3, 2, 2

D:

0, 0, 0

Answer: D

When an automatic array is partially initialized, the remaining elements are initialized to 0.

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What is the output of the program

#include<stdio.h>
int main()
{
    extern int fun(float);
    int a;
    a = fun(3.14);
    printf("%d\n", a);
    return 0;
}
int fun(int aa)
{
	return (int)++aa;
}

A:

3

B:

3.14

C:

0

D:

4

Answer: E

2 Errors
1. Type mismatch in redeclaration of fun
2. Type mismatch in parameter aa

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What is the output of the program

#include<stdio.h>
int main()
{
    int x = 10, y = 20, z = 5, i;
    i = x < y < z;
    printf("%d\n", i);
    return 0;
}

A:

0

B:

1

C:

Error

D:

None of these

Answer: B

Since x < y turns to be TRUE it is replaced by 1. Then 1 < z is compared and to be TRUE. The 1 is assigned to i.

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What will be the output of the program?

#include<stdio.h>
int X=40;
int main()
{
    int X=20;
    printf("%d\n", X);
    return 0;
}

A:

20

B:

40

C:

Error

D:

No Output

Answer: A

Whenever there is conflict between a local variable and global variable, the local variable gets priority.

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Questions for: Declarations And Initializations