如何在Java中全局声明数组?

如何在Java中全局声明数组?,java,arrays,Java,Arrays,我有一个java程序,它将两个矩阵相乘。我在全局错误声明中发现了一些错误。 这是我的密码 import java.util.Scanner; /**WAP in Java for multiplication of two (m*n) matrices. */ public class PracProg_7{ static int m,n,p; static int a[][]; static int b[][];

我有一个java程序,它将两个矩阵相乘。我在全局错误声明中发现了一些错误。 这是我的密码

import java.util.Scanner;

    /**WAP in Java for multiplication of two (m*n) matrices. */
    public class PracProg_7{
        static int m,n,p;
        static int a[][];
        static int b[][];
        static int c[][];
        public static void main(String[] args){
            getMatrix();
            solveMatrix();
            display();

        }
        static void getMatrix(){
            int i,j;
            System.out.println("Enter size of matrix  || Enter m,n,p");
            Scanner sc = new Scanner(System.in);
            m = sc.nextInt();
            n = sc.nextInt();
            p = sc.nextInt();
            int a[][] = new int [m][n];
            int b[][] = new int [n][p];

            System.out.println("Enter matrix A");
            for(i=0;i<m;i++){
                for(j=0;j<n;j++){
                    a[i][j] = sc.nextInt();
                }
            }
            System.out.println("Enter matrix B");
            for(i=0;i<n;i++){
                for(j=0;j<p;j++){
                    b[i][j] = sc.nextInt();
                }
            }

        }
        static void solveMatrix(){
            int i,j,k;
            int c[][] = new int [m][p];
            for(i=0;i<m;i++) {
                for (j = 0; j < p; j++) {
                    c[i][j] = 0;
                    for (k = 0; k < n; k++) {
                        try{
                        c[i][j] += a[i][k] * b[k][j];
                    }
                    catch (ArrayIndexOutOfBoundsException e){System.out.println("Error" + e);}
                    }
                }
            }
        }
        static void display(){
            int i,j;
            for(i=0;i<m;i++){
                for(j=0;j<p;j++){
                    System.out.print(c[i][j] + "\t");
                }
                System.out.println();
            }
        }
    }

这是因为在getMatrix()方法中,没有使用数组对象实例变量a和b,而是创建a和b数组的新本地副本

您需要在getMatrix()中更改a和b,如下所示:

a= new int [m][n];
b = new int [n][p];
您可以在下面找到更新的getMatrix()方法:

static void getMatrix(){
        int i,j;
        System.out.println("Enter size of matrix  || Enter m,n,p");
        Scanner sc = new Scanner(System.in);
        m = sc.nextInt();
        n = sc.nextInt();
        p = sc.nextInt();
        a= new int [m][n];
        b = new int [n][p];

        System.out.println("Enter matrix A");
        for(i=0;i<m;i++){
            for(j=0;j<n;j++){
                a[i][j] = sc.nextInt();
            }
        }
        System.out.println("Enter matrix B");
        for(i=0;i<n;i++){
            for(j=0;j<p;j++){
                b[i][j] = sc.nextInt();
            }
        }

    }
static void getMatrix(){
int i,j;
System.out.println(“输入矩阵的大小| |输入m,n,p”);
扫描仪sc=新的扫描仪(System.in);
m=sc.nextInt();
n=sc.nextInt();
p=sc.nextInt();
a=新整数[m][n];
b=新整数[n][p];
System.out.println(“输入矩阵A”);

对于(i=0;iAdd错误消息,请回答您的问题。您在函数阴影静态数组中声明a/b/c数组,请从函数内部声明中删除int[][]talex的可能副本我是初学者请不要否决我的问题
static void getMatrix(){
        int i,j;
        System.out.println("Enter size of matrix  || Enter m,n,p");
        Scanner sc = new Scanner(System.in);
        m = sc.nextInt();
        n = sc.nextInt();
        p = sc.nextInt();
        a= new int [m][n];
        b = new int [n][p];

        System.out.println("Enter matrix A");
        for(i=0;i<m;i++){
            for(j=0;j<n;j++){
                a[i][j] = sc.nextInt();
            }
        }
        System.out.println("Enter matrix B");
        for(i=0;i<n;i++){
            for(j=0;j<p;j++){
                b[i][j] = sc.nextInt();
            }
        }

    }