线程“main”中的Java数组帮助异常[重复]

Question

初学者在这里，我需要帮助这个例外越界错误。我真的卡住了！试图将矩阵相乘。请帮忙

package arrayPractice1;

import java.util.Arrays;
import java.util.Scanner;

public class Array {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Type how much rows will matrix A have");
        int rowA = in.nextInt();
        System.out.println("Type how much columns will matrix A have");
        int colA = in.nextInt();
        System.out.println("Type how much rows will matrix B have");
        int rowB = in.nextInt();
        System.out.println("Type how much columns will matrix B have");
        int colB = in.nextInt();

        int[][] matrixA = new int[rowA][colA];
        int[][] matrixB = new int[rowB][colB];

        for (int i = 0; i < matrixA.length; i++) {
            for (int j = 0; j < matrixA[i].length; j++) {
                System.out.println("Enter value for row " + i + " and column " + j);
                matrixA[i][j] = in.nextInt();
            }
        }

        for (int i = 0; i < matrixB.length; i++) {
            for (int j = 0; j < matrixB[i].length; j++) {
                System.out.println("Enter value for row " + i + " and column " + j);
                matrixB[i][j] = in.nextInt();
            }
        }

        in.close();

        int[][] multiply = new int[colA][rowB];
        int sum = 0;

        System.out.println("Mult. of matrixA and matrixB");

        for (int i = 0; i < rowA; i++) {
            for (int j = 0; i < colB; j++) {
                for (int k = 0; k < rowA; k++) {
                    sum = sum + matrixA[i][k] * matrixB[k][j];
                }
                multiply[i][j] = sum;
                sum = 0;
            }
        }

        System.out.println(Arrays.deepToString(multiply));

    }

}

Answer 1

for (int i = 0; i < rowA; i++) {
        for (int j = 0; i < collB; j++) {
            for (int k = 0; k < rowA; k++) {
                sum = sum + matrixA[i][k] * matrixB[k][j];
            }
            multiply[i][j] = sum;
            sum = 0;
        }
    }

在这里，您正在检查i是否小于collB，当这是真的时，您正在使j大于矩阵[k][j]允许的值，从而导致索引越界错误。