Ref Functions? Easy

/*
    Rectangle Area v1
    Created by Julio Milian
    July 27, 2016

    This program will calculate the area
    of a rectangle based on users length
    and width.
*/

#include <iostream>
using namespace std;


int main(){

    //function prototypes
    double getLength(int &);
    double getWidth(int &);
    double getArea(double &, double &);
    void displayData(double &, double &, double &);

    //VARIABLES
    int length = 0;
    int width = 0;
    double newLen = 0.0;
    double newWid = 0.0;
    double area = 0.0;

    for (;;){

        cout << "Rectangle Area v1\n";
        cout << "Enter -1 as a value if wish to quit!\n";
        cout << "-------------------------------------\n";
        cout << "What is the lenght? ";
        cin >> length;
        if (length != -1){
            cout << "What is width? ";
            cin >> width;
            newLen = getLength(length);
            newWid = getWidth(width);
            area = getArea(newLen, newWid);
            displayData(newLen, newWid, area);
        }
        else if(length <= 0 && length != -1)
            cout << "\nNo negative numbers!";
        else{
            cout << "\n\nExiting. . . ";
            return 0;
        }//end if
        system("Pause");
        system("CLS");
    }//end for

    return 0;
}//end main

//-------Functions--------
double getLength(int &ref){
    double one = 1.0;
    ref = ref * one;
    return ref;
}

double getWidth(int &ref){
    double one = 1.0;
    ref = ref * one;
    return ref;
}

double getArea(double &refa, double &refb){
    double area = 0.0;
    area = refa * refb;
    return area;
}

void displayData(double &refa, double &refb, double &refc){
    cout << "\nResults\n";
    cout << "--------------------------------------\n";
    cout << "The length of the rectangle is: " << refa;
    cout << "\nThe widht of the rectangle is: " << refb;
    cout << "\nThe area of the rectangle is: " << refc << "\n\n";
}