>>196
systemコマンドでcat file_1 file_2 ... > file_n の方法でよければ。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main(int argc, char *argv[])
{
int i;
char s[100] = "", *p = s;
strcpy(p,"cat ");
for (i = 1; i <= argc-2; i++) {
for(;*p;p++);
sprintf(p,"%s ",argv[i]);
}
for(;*p;p++);
sprintf(p," > %s ",argv[i]);
system(s);
return 0;
}