C interview Questions

What will print out?

main()
{ 
        char *p1=“name”; 
        char *p2;
        p2=(char*)malloc(20);
        memset (p2, 0, 20);
        while(*p2++ = *p1++); 
        printf(“%sn”,p2);

}

Answer:empty string.

What will be printed as the result of the operation below:

main()
{ 
    int x=20,y=35;
    x=y++ + x++;
    y= ++y + ++x; 
    printf(“%d%dn”,x,y);

}

Answer : 5794

What will be printed as the result of the operation below:

main()
{
    int x=5;
    printf(“%d,%d,%dn”,x,x< <2,x>>2);

}

Answer: 5,20,1

What will be printed as the result of the operation below:

#define swap(a,b) a=a+b;b=a-b;a=a-b;

void main()
{
    int x=5, y=10;
    swap (x,y);
    printf(“%d %dn”,x,y);
    swap2(x,y);
    printf(“%d %dn”,x,y);
}

int swap2(int a, int b)
{
    int temp;
    temp=a;
    b=a;
    a=temp;
    return 0;

}

Answer: 10, 5
10, 5