C / C++ / MFC

<br />
#include <stdlib.h><br />
#include <stdarg.h><br />
#include <stdio.h><br />
<br />
int maxof(int, ...) ;<br />
void f(void);<br />
<br />
main(){<br />
        f();<br />
        exit(EXIT SUCCESS);<br />
}<br />
<br />
int maxof(int n_args, ...){<br />
        register int i;<br />
        int max, a;<br />
        va_list ap;<br />
<br />
        va_start(ap, n_args);<br />
        max = va_arg(ap, int);<br />
        for(i = 2; i <= n_args; i++) {<br />
                if((a = va_arg(ap, int)) > max)<br />
                        max = a;<br />
        }<br />
<br />
        va_end(ap);<br />
        return max;<br />
}<br />
<br />
void f(void) {<br />
        int i = 5;<br />
        int j[256];<br />
        j[42] = 24;<br />
        printf("%d\n",maxof(3, i, j[42], 0));// Anyone can explain this by step-by-step?<br />
}