Problem with calling a function within a function

Question

My problem is with the getWidth and getLength functions. The problem I am having is with the fact that when I get an incorrect input I pass it through the function again, which give me a weird return. The return I get is the correct input plus all the previous incorrect inputs after that. The one that gets returned is first incorrect input? I don't know if you understand, but I would appreciate help for this beginner.
**Sorry about posting in this forum... I just realized this is not for beginners. Help would still be appreciated.**
import java.util.Scanner;
//Calculates the area of a rectangle
public class AreaRectangle {
    private static Scanner c = new Scanner(System.in);
    private static boolean isNumber(String in) {
        boolean isNum = false;
        int count = 0;
        for (int i=0;i<in.length();i++) {
            if (in.charAt(i) >= '0' && in.charAt(i) <= '9' || in.charAt(i) == '.') {
                if (in.charAt(i) == '.') {count++;}
                else if (count > 1){isNum=false;break;}
                else {isNum = true;}
            else {
                isNum=false;
                break;
        return isNum;
    public static double getLength() {
        String input;
        boolean isNum;
        double length = 0;
        System.out.print("Please enter the rectangle's length: ");
        input = c.nextLine();
        isNum = isNumber(input);
        if (isNum) {
            length = Double.parseDouble(input);
        else {
            System.out.println("Incorrect input!");
            getLength();
        System.out.println(input);
        return length;
    public static double getWidth() {
        String input;
        boolean isNum;
        double width = 0;
        System.out.print("Please enter the rectangle's width: ");
        input = c.nextLine();
        isNum = isNumber(input);
        if (isNum) {
            width = Double.parseDouble(input);
        else {
            System.out.println("Incorrect input!");
            getWidth();
        System.out.println(input);
        return width;
    public static double getArea(double length, double width) {
        return width*length;
    public static void displayData(double length, double width, double area) {
        System.out.println("Width = "+width+" "+"Length = "+length+" "+"Area = "+area);
    public static void main(String[] args) {
        double l, w, a;
        l = getLength();
        w = getWidth();
        a = getArea(l, w);
        displayData(l, w, a);
}Edited by: x713 on Apr 12, 2008 7:12 PM
Edited by: x713 on Apr 12, 2008 7:19 PM

Answer 1

You're calling things recursively and that's not good (at least not here).
To clarify, please look:
    public static double getLength() {
        if (something) {
            do something else
        else {
            System.out.println("Incorrect input!");
            getLength();  // you call the entire method again here! This is the recursive call
    }Better is to have a while loop inside the method and repeat this loop until the input that the user enters is correct (or until they quits).