CODEWITHSUNDEEP
javaarrays
user12245018
user12245018

Reputation:

How would I stop a negative value from input being stored in an array?

The code takes an x and y coordinate, however I don't want any negative values to be stored in the array. How would I go about in doing this as I can only break away from the loop but can't seem to avoid storing the negative value.

import java.util.Scanner;

class ConvexHull {

    static int loadPoints(int maxPoints, double[] xVal, double[] yVal) {
        int numPoints = 0;
        Scanner scan = new Scanner(System.in);

        for(int i = 0; i < xVal.length; i++) {
            System.out.println("Insert a x value: ");
            xVal[i] = scan.nextDouble();
            if(xVal[i] < 0) {
                break;
            }
            if(xVal[i] > maxPoints) {
                System.out.println("Maximum capacity for array has been reached");
                break;
            }

            System.out.println("Insert a y value: ");
            yVal[i] = scan.nextDouble();
            if(yVal[i] < 0) {
                break;
            }
            if(yVal[i] > maxPoints) {
                System.out.println("Maximum capacity for array has been reached");
                break;
            }
        }
        numPoints = yVal.length;
        scan.close();
        return numPoints;   
    }

    public static void main(String[] args) {
    int maxPoints = 70;
    double[] xVal = new double[maxPoints];
    double[] yVal = new double[maxPoints];
    loadPoints(maxPoints, xVal, yVal);
    for(int x= 0; x < xVal.length; x++) {
            System.out.println(xVal[x] + "," + yVal[x]);
        }


    }
}

Upvotes: 1

Views: 720

Answers (2)

WJS
WJS

Reputation: 40034

Test the value first. But if you have different arrays of the same type, make a method.

public static int insert(double[] arr, double val, int i) {
    if(i >= arr.length) {
       System.out.println("Array has reached capacity");
       return -2;
    }
    if (val < 0) {
      return -1;
    }
    arr[i] = val;
    return 0; // ok.
}

Upvotes: 0

Brydenr
Brydenr

Reputation: 798

The problem is that doing xVal[i] = scan.nextDouble(); puts the value into the array before the check. Doing something like

// Read in the next double
double nextX = scan.nextDouble();

// If the next double is negative, break out of the loop
if (nextX < 0) {
    break;
}
xVal[i] = nextX;

...
// Same format for yVal

Upvotes: 1

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