Input from command line

Question

I have a program in C++ which I run for many values of a parameter. What I want to do is the following: Let's say I have two parameters as:

int main(){
    double a;
    double b;
//some more lines of codes
}

Now after after I compile I want to run it as

./output.out 2.2 5.4

So that a takes the value 2.2 and b takes the value 5.4.

Of course one way is to use cin>> but I cannot do that because I run the program on a cluster.

Answer 1

You need to use command line arguments in your main:

int main(int argc, char* argv[]) {
    if (argc != 3) return -1;
    double a = atof(argv[1]);
    double b = atof(argv[2]);
    ...
    return 0;
}

This code parses parameters using atof; you could use stringstream instead.