GCD C++ program

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

void testints(int *x, int *y);


int GCD(int x, int y) //take in the two variables
{
    while( 1 ) //while true
    {
        if( y == 0 ){ //if y =0 then according to the assignment, the GCD is x
            return x;
        }
        else{
            x = x % y;
            if( x == 0 )
                return y;
            y = y % x;
        }

    }
}
int inputargs(int argumentnum){
    int x;
    char a[256];
    cout << "Please enter positive integers for" << endl;
    cout << "Value "<< argumentnum<<": ";
    cin >> a;
    x=atoi ( a );
    return x; // Return User input
}
void testints(int& x, int& y) {
    while ( x<=0 || y<0 || (x<=0 && y<0)){
        cin.clear();
        cin.ignore(100, '\n');
        char a[256];
        char b[256];
        cout << "Invalid input" << endl;
        cout << "Please enter positive integers for" << endl;
        cout << "Value 1: ";
        cin >> a;
        x=atoi (a);
        cout << "Value 2: ";
        cin >> b;
        y=atoi (b);
    }
}
void printresults(int x, int y){
    cout << "\nThe Greatest Common Divisor of "<< x << " and " << y << " is " << GCD(x, y) << endl;
    system("PAUSE"); //stops the dialog window from closing, though this issue didn't happen before. Will research this later.
}
int main(int argc, char ** argv){
    if (argc <=0){ //something weird has happened, terminate
        cout << "A Critical Error has occured, system is terminating" << endl;
        exit (1);
    }
    if (argc == 1) //Zero Prompts
    {
        int argnum1=1;
        int x = inputargs(argnum1);
        int argnum2=2;
        int y = inputargs(argnum2);
        testints(x,y);
        printresults(x,y);
    }
    if (argc == 2) // One Command Line
    {
        int x;
        x=atoi(argv[1]);
        int argnum2=2;
        int y = inputargs(argnum2);
        testints(x,y);
        printresults(x,y);
    }
    if (argc == 3) // Two Command Line
    {
        int x,y;
        x=atoi(argv[1]);
        y=atoi(argv[2]);
        testints(x,y);
        printresults(x,y);
    }
    if (argc > 3) // More then Two Command Line
    {
        cout << "You have entered more than three inputs" << endl;
        cout << "We will only use the first two inputs" << endl;
        cout << "Hit enter to acknowledge and continue..." << endl;
        int x,y;
        x=atoi(argv[1]);
        y=atoi(argv[2]);
        testints(x,y);
        printresults(x,y);
    }
    else{
        return 0;
    }
}