我在stackoverflow中搜索了我的答案，但我找不到它，我自己尝试了大约一个小时的相关答案

Question

这实际上是一个矩阵的乘法....

import java.util.Scanner;
class MatMu {
    public static void main(String args[]) {
        int a[][] = new int[3][3];
        int b[][] = new int[3][3];
        int c[][] = new int[3][3];
        System.out.println("enter the first matrix:");
        for (int i = 0; i < 3; i++)
            for (int j = 0; j < 3; j++)
                a[i][j] = input.nextInt();
        System.out.println("enter the second matrix:");
        for (int i = 0; i < 3; i++)
            for (int j = 0; j < 3; j++)
                b[i][j] = input.nextInt();
        System.out.println("matrix mutiplication is as follows:");
        Scanner input = new Scanner(System.in);
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = 0;
                for (int k = 0; k < 3; k++) {
                    c[i][j] += a[i][k] * b[k][i];
                }
            }
        }
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                System.out.println(a[i][j] + "t");
            }
            System.out.println("n");
        }
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                System.out.println(b[i][j] + "t");
            }
            System.out.println("n");
        }
        System.out.println("n");
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                System.out.println(c[i][j] + "t");
            }
            System.out.println("n");
        }
    }
}

错误是在a[i][j]=input.nextInt()和b[i][j]=input.nextInt():找不到符号....这是一个java程序我找不到符号也就是a和b

Answer 1

您没有定义输入，我猜是Scanner之前的第一次使用。在开始时定义这个扫描器，然后使用它。

Answer 2

您正在访问未在代码顶部初始化的扫描仪对象:

Scanner input=new Scanner(System.in); 

写如下代码:

 public static void main(String args[])
            {
         Scanner input=new Scanner(System.in);
     /* your code */
    }

Answer 3

import java.util.Scanner;
class MatMu {
public static void main(String args[]) {
    int a[][] = new int[3][3];
    int b[][] = new int[3][3];
    int c[][] = new int[3][3];

    Scanner input = new Scanner(System.in);  // pasted it here
    System.out.println("enter the first matrix:");
    // your code
    //  Scanner input = new Scanner(System.in);  // moving this line to top
    // your next code...
}