Thread: Quick input check question

So I want to check to see if the command line argument I received was an integer. How do I do this?

Code:

#include <iostream>
using namespace std;

int main(int argc, char* argv[]) {
	//**************************
	//Checking for correct input
	//**************************

	if ( argc != 2 ) {
		cerr << "Usage: " << argv[0] << " n" << endl;
		return 1;
    }

	if ( argv[1].isdigit() != 1 && ) {
		cerr << "Usage: n must be a positive integer." << endl;
		return 1;
	}
}

However, the error message says that there is a request for member isdigit in *(argv + 4u) which is of nonclass type char*.

I don't really understand the error message.