随笔档案(496)

//转载请注明出处：http://hi.baidu.com/jadmin/blog/item/163ed2f8a8e88b0dd8f9fd46.html
/**
* @(#)MatrixMultiply.java
*
*
* @author JAdmin
* @version 1.00 2007/8/21
*/

import java.util.Scanner;

public class MatrixMultiply
{
public static void main(String[] args)
{
    int m,n,p;
    System.out.println("请输入3个矩阵参数m,n,p.示例a[m][n]*b[n][p]=c[m][p]");
    Scanner sr = new Scanner(System.in);
    System.out.print("m=");
    m = sr.nextInt();
    System.out.print("n=");
    n = sr.nextInt();
    System.out.print("p=");
    p = sr.nextInt();

    int[][] a = new int[m][n];
    int[][] b = new int[n][p];
    int[][] c = new int[m][p];

    System.out.println("请输入数组a[" + m + "][" + n + "]");
    input(a);
    System.out.println("请输入数组b[" + n + "][" + p + "]");
    input(b);

    //以下开始计算c[][]
    for(int i = 0;i < c.length;i++)
     for(int j = 0;j < c[0].length;j++)
      c[i][j] = getMultiItem(a,b,i,j);

    System.out.println("************The matrix a[][]************");
    display(a);
    System.out.println("************The matrix b[][]************");
    display(b);
    System.out.println("************The matrix c[][]************");
    display(c);
}

private static void input(int[][] arr)
{
    Scanner sr = new Scanner(System.in);
    for(int i = 0;i < arr.length;i++)
     for(int j = 0;j < arr[0].length;j++)
       arr[i][j] = sr.nextInt();
}

private static void display(int[][] arr)
{
    for(int i = 0;i < arr.length;i++)
    {
     for(int j = 0;j < arr[0].length;j++)
      System.out.print(arr[i][j]+" ");
     System.out.println();
    }
}

private static int getMultiItem(int[][] a,int[][] b,int p,int q)
{
    //计算元素c[p][q]
    int tmp = 0;

    for(int i = 0;i < a[0].length;i++)
     tmp += a[p][i]*b[i][q];
    return tmp;
}
}