What will be the output of the program?

#include<stdio.h>
#include<math.h>
int main()
{
    float n=1.54;
    printf("%f, %f\n", ceil(n), floor(n));
    return 0;
}

/* sample.c */
#include<stdio.h>

int main(int argc, char *argv[])
{
    int i=0;
    i+=strlen(argv[1]);
    while(i>0)
    {
        printf("%c", argv[1][--i]);
    }
    return 0;
}

struct emp
{
    int ecode;
    struct emp *e;
};

#include<stdio.h>

int main()
{
    union a
    {
        int i;
        char ch[2];
    };
    union a z1 = {512};
    union a z2 = {0, 2};
    return 0;
}

struct emp
{
    int ecode;
    struct emp e;
};

/* sample.c */
#include<stdio.h>

int main(int argc, char *argv[])
{
    printf("%c", **++argv);
    return 0;
}