Point out the error in the following program.

#include<stdio.h>
#include<stdarg.h>
fun(...);

int main()
{
    fun(3, 7, -11.2, 0.66);
    return 0;
}
fun(...)
{
    va_list ptr;
    int num;
    va_start(ptr, n);
    num = va_arg(ptr, int);
    printf("%d", num);
}

/* 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;
}

#include<stdio.h>

int main()
{
    char far *near *ptr1;
    char far *far *ptr2;
    char far *huge *ptr3;
    printf("%d, %d, %d\n", sizeof(ptr1), sizeof(ptr2), sizeof(ptr3));
    return 0;
}

#include<stdio.h>

int main()
{
    char huge *near *far *ptr1;
    char near *far *huge *ptr2;
    char far *huge *near *ptr3;
    printf("%d, %d, %d\n", sizeof(ptr1), sizeof(*ptr2), sizeof(**ptr3));
    return 0;
}