#include <stdio.h> #include <stdlib.h> // itoa() and ltoa() #include <string.h> // strcat() and strlen() // echo("$i, $s, $l, $c", arg1, arg2, arg3, arg4) // $i -- int, $s -- string, $l -- long, $c -- char void echo(char *fmt, ...) {     int i, fmtlen = strlen(fmt);     int *args = (int *)((char *)(&fmt) +sizeof(char *));     char cbuff[BUFSIZ] = {'\0'}, nbuff[BUFSIZ] = {'\0'}; // #define BUFSIZ 512 in <stdio.h>     for (i = 0; i < fmtlen; i++)     {         if (('$' == fmt[i]) && ((i + 1) < fmtlen))         {             switch (fmt[i + 1])             {             case 's': strcat(cbuff, (char *)(*args));                 break;             case 'c': cbuff[strlen(cbuff)] = (char)(*args);                 break;             case 'i': itoa(*args, nbuff, 10); strcat(cbuff, nbuff);                 break;             case 'l': ltoa((long)(*args), nbuff, 10); strcat(cbuff, nbuff);                 break;             default: break;             }             ++args, ++i;         }         else             cbuff[strlen(cbuff)] = fmt[i];     }     cbuff[strlen(cbuff) + 1] = '\0';     fputs(cbuff, stdout); } int main() {     echo("arg_list = $i, $s, $l, $c", 2, "hello", 8, 'a'); // Si -- %d, $s -- %s, $l -- %ld, $c -- %c     return 0; }