44 lines
1.5 KiB
C
44 lines
1.5 KiB
C
/*
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* Copyright (c) 2022–2024 DTB <trinity@trinity.moe>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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#include <stdio.h> /* fprintf(3), stderr */
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#include <stdlib.h> /* size_t */
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#include <sysexits.h> /* EX_USAGE */
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char *program_name = "strcmp";
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int main(int argc, char *argv[]){
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if (argc < 3) {
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fprintf(stderr, "Usage: %s string string...\n",
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argv[0] == NULL ? program_name : argv[0]
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);
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return EX_USAGE;
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}
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/* This compares the Nth character of arg[2] onward with argv[1]'s Nth
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* character, rather than comparing each arg with argv[1] sequentially. */
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for (; *argv[1] != '\0'; ++argv[1]) { /* iterate chars in argv[1] */
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for (size_t i = 2; i < argc; ++argv[i], ++i) { /* iterate &argv[2] */
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/* this never overruns because of nul termination */
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if (*argv[i-1] != *argv[i]) { return *argv[i-1] - *argv[i]; }
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}
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}
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return 0;
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}
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