Java 矩阵
public class MatrixTest {
public static void main(String[] args) {
// TODO Auto-generated method stub
//创建矩阵
int[][] a = new int[3][4];
int[][] b = new int[3][4];
int[][] c = new int[4][4];
//矩阵赋值
a=Matrix_value(a);
b=Matrix_value(b);
//输出矩阵
System.out.println("============== 矩阵A ==================");
Matrix_Show(a);
System.out.println("============== 矩阵B ==================");
Matrix_Show(b);
// 加法
System.out.println("============== 矩阵A + 矩阵B ============");
Matrix_Add(a, b);
// 减法
System.out.println("============== 矩阵A - 矩阵B ============");
Matrix_Sub(a, b);
// 乘法
c=Matrix_value(c);
System.out.println("============== 矩阵C ==================");
Matrix_Show(c);
System.out.println("============== 矩阵A * 矩阵C ============");
Matrix_Mul(a, c);
//数乘
System.out.println("============== 2 * 矩阵A =================");
Matrix_Mul(2, a);
//转置
System.out.println("============== 矩阵A转置 =====================");
Matrix_Tran(a);
//旋转
System.out.println("============== 矩阵旋转 =====================");
for (int i = 1; i <= 3; i++) {
System.out.println("============== 旋转 " + i + " 次（每次旋转90度） =====================");
a = Matrix_Rotate(a);
Matrix_Show(a);
}
//对角线之差
System.out.println("============== 矩阵对角线之差 =====================");
Matrix_Diag(a);
}
// 矩阵赋值
public static int[][] Matrix_value(int[][] a) {
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
a[i][j] = (int) (Math.random() * 100 + 1);
}
}
return a;
}
// 输出矩阵
public static void Matrix_Show(int[][] a) {
// ((a));
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
System.out.print(a[i][j] + " ");
}
System.out.println();
}
}
// 加法
public static void Matrix_Add(int[][] a, int[][] b) {
int[][] result = new int[a.length][a[0].length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++) {
result[i][j] = a[i][j] + b[i][j];
}
}
Matrix_Show(result);
}
// 减法
public static void Matrix_Sub(int[][] a, int[][] b) {
int[][] result = new int[a.length][a[0].length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++) {
result[i][j] = a[i][j] - b[i][j];
}
}
Matrix_Show(result);
}
// 乘法
public static void Matrix_Mul(int[][] a, int[][] b) {
int[][] result = new int[a.length][b[0].length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++) {
for (int k = 0; k < b.length; k++) {
result[i][j] += a[i][k] * b[k][j];
}
}
}
Matrix_Show(result);
}
// 数乘
public static void Matrix_Mul(int n, int[][] a) {
int[][] result = new int[a.length][a[0].length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++) {
result[i][j] = a[i][j] * n;
}
}
Matrix_Show(result);
}
// 矩阵转置
public static void Matrix_Tran(int[][] a) {
int[][] result = new int[a[0].length][a.length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++) {
result[i][j] = a[j][i];
}
}
Matrix_Show(result);
}
// 矩阵旋转
public static int[][] Matrix_Rotate(int[][] a) {
// 获得原矩阵的宽高
// 外层一维数组的长度
int w = a.length;
// 内层一维数组的长度
int h = a[0].length;
// 创建一个新二维数组
int[][] c = new int[h][w];
// 原数组的读取位置
int x = w - 1;
int y = 0;
// 将原的二维数组反转90度，赋值到新的二维数组中
for (int i = 0; i < c.length; i++) {
for (int j = 0; j < c[i].length; j++) {
c[i][j] = a[x][y];
x--;
}
// 换行赋值
x = w - 1;
y++;
}
// 旋转90度之后的结果
return c;
}
// 矩阵对角线之差
public static void Matrix_Diag(int[][] a) {
// 主对角线
int x = 0;
// 次对角线
int y = 0;
// 外层一维数组的长度
int i = 0;
// 内层一维数组的长度
int j = 0;
// 求主对角线值
while ((i < a.length) && (j < a[0].length)) {
x += a[i][j];
i++;
j++;
}
i = 0;
j = a[0].length - 1;
// 求次对角线值
while ((i < a.length) && (j >= 0)) {
y += a[i][j];
i++;
j--;
}
System.out.println("矩阵对角线之差为 " + (x - y));
}
}