In the following program how long will the for loop get executed?

#include<stdio.h>
int main()
{
    int i=5;
    for(;scanf("%s", &i); printf("%d\n", i));
    return 0;
}

#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;
}

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

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

#include<stdio.h>
int main()
{
    enum status { pass, fail, atkt};
    enum status stud1, stud2, stud3;
    stud1 = pass;
    stud2 = atkt;
    stud3 = fail;
    printf("%d, %d, %d\n", stud1, stud2, stud3);
    return 0;
}

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

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

#include<stdio.h>
int main()
{
    char *s1;
    char far *s2;
    char huge *s3;
    printf("%d, %d, %d\n", sizeof(s1), sizeof(s2), sizeof(s3));
    return 0;
}

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

#include<stdio.h>
int main()
{
    struct emp
    {
        char name[20];
        int age;
        float sal;
    };
    struct emp e = {"Tiger"};
    printf("%d, %f\n", e.age, e.sal);
    return 0;
}

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