java - 如何阻止输入中的负值存储在数组中？

Question

该代码采用 x 和 y 坐标，但我不希望在数组中存储任何负值。我将如何去做这件事，因为我只能脱离循环，但似乎无法避免存储负值。

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]);
        }


    }
}

Answer 1

问题在于，执行xVal[i] = scan.nextDouble(); 在检查之前将值放入数组中。做类似的事情

// 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