C++ command-line arguments
Sometimes it’s helpful to create your own terminal commands. This can be done as explained in creating custom terminal commands, but if your custom command runs another program, receiving inputs (like the two numbers above) from the custom command to your program is another matter.
Every widely-used general-purpose programming language has a way to get command line arguments. Most languages have libraries to help with the parsing, such as Python’s argparse library or Go’s flag and Cobra libraries. There are third-party libraries for this for C++, but if you don’t want to use one of those, you can do the parsing yourself as shown below.
#include <iostream>
using namespace std;
int main(int argc, char* argv[])
{
int sum = 0;
for (int i = 1; i < argc; i++)
{
sum += atoi(argv[i]);
if (i < argc - 1)
cout << argv[i] << " + ";
}
cout << argv[argc - 1] << " = " << sum << endl;
return 0;
}
The unusual part is that the main function is taking inputs, int argc, char* argv[]. The parameter names argc and argv can be almost anything you want, but their types and order are important. argv (or whichever name you choose) is an array of c-strings of all the inputs to the program (the argument values). argc is the size of the argv array (the argument count). The first element of argv is always the path to the program.
After setting up a custom terminal command for this (example below), using the terminal command add 267 917 puts the value "267" in argv[1] and "917" in argv[2]. As shown above, these c-strings of numbers can then be converted to ints with the atoi function and added together.
For the custom terminal command, I followed the steps in creating custom terminal commands and created this PowerShell function:
function add {
& "C:\Users\chris\source\repos\Project1\x64\Debug\Project1.exe" $args
}