java实验四 数组

1、矩阵的转置：设计一个3X4的矩阵C，输入该矩阵，并且输入该矩阵的转置C’
2、实现两个矩阵的乘积（A*B）和点乘（A.*B），示例如下：

//lsy
package java_experiments;

import java.util.Scanner;

public class four_one {

	public static void transform() {
		Scanner input = new Scanner(System.in);
		int[][] a = new int[3][4];
		int[][] b = new int[4][3];
		System.out.println("输入三行四列的矩阵:");
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				int num = input.nextInt();
				a[i][j] = num;
				b[j][i] = a[i][j];
			}
		}
		System.out.println("转置前:");
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				System.out.print(a[i][j] + "t");
			}
			System.out.println();
		}
		System.out.println("转置后:");
		for (int i = 0; i < b.length; i++) {
			for (int j = 0; j < b[i].length; j++) {
				System.out.print(b[i][j] + "t");
			}
			System.out.println();
		}
		input.close();
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		transform();
	}

}

//lsy
package java_experiments;

import java.util.Scanner;

public class four_two {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		System.out.println("输入第一个矩阵行数和列数:");
		int i1 = input.nextInt();
		int j1 = input.nextInt();
		int[][] a = new int[i1][j1];
		System.out.println("输入第一个矩阵:");
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				int num = input.nextInt();
				a[i][j] = num;
			}
		}
		System.out.println("输入第二个矩阵行数和列数:");
		int i2 = input.nextInt();
		int j2 = input.nextInt();
		int[][] b = new int[i2][j2];
		System.out.println("输入第二个矩阵:");
		for (int i = 0; i < b.length; i++) {
			for (int j = 0; j < b[i].length; j++) {
				int num = input.nextInt();
				b[i][j] = num;
			}
		}
		Cheng(a, b);
		System.out.println("===============");
		DianCheng(a, b);
		input.close();
	}

	// 矩阵乘矩阵
	public static void Cheng(int a[][], int b[][]) {
		int[][] c = new int[a.length][b[0].length];
		if (a[0].length == b.length) {
			for (int i = 0; i < c.length; i++) {
				for (int j = 0; j < c[i].length; j++) {
					for (int k = 0; k < b.length; k++) {
						c[i][j] += a[i][k] * b[k][j];
					}
				}
			}
		} else {
			System.out.println("A 的列数不等于 B 的行数");
		}
		System.out.println("矩阵相乘后:");
		for (int i = 0; i < c.length; i++) {
			for (int j = 0; j < c[i].length; j++) {
				System.out.print(c[i][j] + "t");
			}
			System.out.println();
		}
	}

	public static void DianCheng(int a[][], int b[][]) {
		int[][] c = new int[a.length][b[0].length];
		if ((a.length == b.length) && (a[0].length == b[0].length)) {
			for (int i = 0; i < c.length; i++) {
				for (int j = 0; j < c[i].length; j++) {
					c[i][j] = a[i][j] * b[i][j];
				}
			}
			System.out.println("矩阵点乘后:");
			for (int i = 0; i < c.length; i++) {
				for (int j = 0; j < c[i].length; j++) {
					System.out.print(c[i][j] + "t");
				}
				System.out.println();
			}
		} else
			System.out.println("矩阵无法进行点乘");
	}
}