overgrown/src/strcmp.c

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/*
* Copyright (c) 20222024 DTB <trinity@trinity.moe>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
#include <stdio.h> /* fprintf(3), stderr */
#include <stdlib.h> /* size_t */
#include <sysexits.h> /* EX_USAGE */
static *program_name = "strcmp";
int main(int argc, char *argv[]){
if (argc < 3) {
fprintf(stderr, "Usage: %s string string...\n",
argv[0] == NULL ? program_name : argv[0]
);
return EX_USAGE;
}
for (; *argv[1] != '\0'; ++argv[1]) { /* iterate chars in ref */
/* iterate argc */
for (size_t i = 2 /* ref cmp */; i < argc; ++argv[i], ++i) {
/* this doesn't overrun because of nul termination */
if (*argv[i-1] != *argv[i]) { return *argv[i-1] - *argv[i]; }
}
}
return 0;
}