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How to parse options in C++ using getopt_long
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| #include <getopt.h> | |
| #include <iostream> | |
| int num = -1; | |
| bool is_beep = false; | |
| float sigma = 2.034; | |
| std::string write_file = "default_file.txt"; | |
| void PrintHelp() | |
| { | |
| std::cout << | |
| "--num <n>: Set number of program\n" | |
| "--beep: Beep the user\n" | |
| "--sigma <val>: Set sigma of program\n" | |
| "--writeFile <fname>: File to write to\n" | |
| "--help: Show help\n"; | |
| exit(1); | |
| } | |
| void ProcessArgs(int argc, char** argv) | |
| { | |
| const char* const short_opts = "n:bs:w:h"; | |
| const option long_opts[] = { | |
| {"num", required_argument, nullptr, 'n'}, | |
| {"beep", no_argument, nullptr, 'b'}, | |
| {"sigma", required_argument, nullptr, 's'}, | |
| {"writeFile", required_argument, nullptr, 'w'}, | |
| {"help", no_argument, nullptr, 'h'}, | |
| {nullptr, no_argument, nullptr, 0} | |
| }; | |
| while (true) | |
| { | |
| const auto opt = getopt_long(argc, argv, short_opts, long_opts, nullptr); | |
| if (-1 == opt) | |
| break; | |
| switch (opt) | |
| { | |
| case 'n': | |
| num = std::stoi(optarg); | |
| std::cout << "Num set to: " << num << std::endl; | |
| break; | |
| case 'b': | |
| is_beep = true; | |
| std::cout << "Beep is set to true\n"; | |
| break; | |
| case 's': | |
| sigma = std::stof(optarg); | |
| std::cout << "Sigma set to: " << sigma << std::endl; | |
| break; | |
| case 'w': | |
| write_file = std::string(optarg); | |
| std::cout << "Write file set to: " << write_file << std::endl; | |
| break; | |
| case 'h': // -h or --help | |
| case '?': // Unrecognized option | |
| default: | |
| PrintHelp(); | |
| break; | |
| } | |
| } | |
| } | |
| int main(int argc, char **argv) | |
| { | |
| ProcessArgs(argc, argv); | |
| return 0; | |
| } | |
| /* | |
| $ g++ -std=c++11 opt.cpp | |
| $ ./a.out --help | |
| --num <n>: Set number of program | |
| --beep: Beep the user | |
| --sigma <val>: Set sigma of program | |
| --writeFile <fname>: File to write to | |
| --help: Show help | |
| $ ./a.out --num 10 | |
| Num set to: 10 | |
| $ ./a.out --num 10 --writeFile haha.txt --sigma 3.45 --beep | |
| Num set to: 10 | |
| Write file set to: haha.txt | |
| Sigma set to: 3.45 | |
| Beep is set to true | |
| */ |
@oxmon_2500 It means 'b' doesn't take any arguments. The colon sign in short_opts is not a separator. It means that the preceding character/option takes arguments. Read the man page for getopt.
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Hi, what does mean bs not separated by collon in short_opts?