[java]代码库import java.util.Scanner;

import java.util.Arrays;

public class Main {

public static void main(String[] args) {

Scanner scan = new Scanner(System.in);

int r = scan.nextInt();

int c = scan.nextInt();

System.out.println("row:"+r+" column:"+c);

//输入，修改矩阵的值

Matrix me = new Matrix(r,c);

for(int i = 0; i < r; i++)

{

for(int j = 0; j < c; j++)

{

double a = scan.nextDouble();

me.set(i, j, a);

}

}

r = scan.nextInt();

c = scan.nextInt();

double a = scan.nextDouble();

me.set(--r, --c, a);

System.out.println("after set value:");

me.show();

//打印具体位置上的值

r = scan.nextInt();

c = scan.nextInt();

System.out.print("value on ("+r+","+c+"):");

System.out.printf("%.0f\n",me.get(--r, --c));

//矩阵相加输出

r = scan.nextInt();

c = scan.nextInt();

Matrix jia = new Matrix(r,c);

for(int i = 0; i < r; i++)

{

for(int j = 0; j < c; j++)

{

a = scan.nextDouble();

jia.set(i, j, a);

}

}

System.out.println("after add:");

(me.add(jia)).show();

//矩阵相乘输出

r = scan.nextInt();

c = scan.nextInt();

Matrix cheng = new Matrix(r,c);

for(int i = 0; i < r; i++)

{

for(int j = 0; j < c; j++)

{

a = scan.nextDouble();

cheng.set(i, j, a);

}

}

System.out.println("after multiply:");

(me.multiply(cheng)).show();

//矩阵转置输出

System.out.println("after transpose:");

(me.transpose()).show();

}

}

class Matrix

{

private int row;//行

private int col;//列

double[][] m;

public Matrix(int a, int b)

{

row = a;

col = b;

m = new double [a][b];

}

void set(int r, int c, double a)

{

m[r][c] = a;

}

double get(int r, int c)

{

return m[r][c];

}

int width()

{

return col;

}

int height()

{

return row;

}

Matrix add(Matrix b)

{

Matrix a = new Matrix(row,col);

for(int i = 0; i < row; i++)

{

for(int j = 0; j < col; j++)

a.set(i,j, b.get(i,j)+this.m[i][j]);

}

return a;

}

Matrix multiply(Matrix b)

{

Matrix a = new Matrix(row,b.width());

for( int i = 0; i < row; i++)

{

for( int j = 0; j < b.width(); j++)

{

int sum = 0;

for( int k = 0; k < col; k++)

sum += this.get(i,k)*b.get(k, j);

a.set(i, j, sum);

}

}

return a;

}

Matrix transpose()

{

Matrix a = new Matrix(col,row);

for(int i = 0; i < col; i++)

{

for(int j = 0; j < row; j++)

a.set(i,j,this.m[j][i]);

}

return a;

}

void show()

{

for(int i = 0; i < row; i++)

{

for(int j = 0; j < col; j++)

{

if( j == 0)

System.out.printf("%.0f",this.get(i, j));

else

System.out.printf(" %.0f",this.get(i, j));

}

System.out.println();

}

}

}