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C Programming - Declarations and Initializations

Exercise : Declarations and Initializations - Find Output of Program
6.
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;
}
20
40
Error
No Output
Answer: Option
Explanation:
Whenever there is conflict between a local variable and global variable, the local variable gets priority.
7.
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;
}
0
1
Error
None of these
Answer: Option
Explanation:
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.
8.
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;
}
3
3.14
0 
4
Compile Error
Answer: Option
Explanation:
2 Errors
1. Type mismatch in redeclaration of fun
2. Type mismatch in parameter aa
9.
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;
}
Garbage Values
2, 3, 3
3, 2, 2
0, 0, 0
Answer: Option
Explanation:
When an automatic array is partially initialized, the remaining elements are initialized to 0.
10.
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;
}
3, 2, 515
515, 2, 3
3, 2, 5
None of these
Answer: Option
Explanation:

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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