釣りダイレクトって読んじゃったよ。
-- 最低限機能版
#include <stdio.h>
int main(int argc, char ** argv)
{
if (argc < 4) return 1;
FILE * in1 = fopen(argv[1], "r");
if (in1 == NULL) return 1;
FILE * in2 = fopen(argv[2], "r");
if (in2 == NULL) return 1;
FILE * out = fopen(argv[3], "w");
if (out == NULL) return 1;
int ch;
while ((ch = fgetc(in1)) != EOF) {
fputc(ch, out);
}
fclose(in1);
while ((ch = fgetc(in2)) != EOF) {
fputc(ch, out);
}
fclose(in2);
fclose(out);
return 0;
}