This example program provides an example of a CLI executable in C/C++ that uses one command line argument and exits with a usage message if that argument is not present:
#include <stdio.h> int main(int argc, char **argv) { if(argc <= 1) { // <= (number of expected CLI arguments) fprintf(stderr, "Usage: %s <input file>\n", argv[0]); return -1; } // TODO Your code goes here! printf("Input file: %s\n", argv[1]); return 0; }
Compile with
g++ -o cli-onearg cli-onearg.cpp
Usage example:
$ ./cli-onearg Usage: ./cli-onearg <input file> $ ./cli-onearg my-input-file.txt Input file: my-input-file.txt