Java实现矩阵乘法

1、当矩阵A的列数（column）等于矩阵B的行数（row）时，A与B可以相乘。

2、矩阵C的行数等于矩阵A的行数，C的列数等于B的列数。

3、乘积C的第m行第n列的元素等于矩阵A的第m行的元素与矩阵B的第n列对应元素乘积之和。

private static int[][] A, B, C;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		A = new int[n][n];
		B = new int[n][n];
		C = new int[n][n];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				A[i][j] = sc.nextInt();
				B[i][j] = A[i][j];
			}
		}

        if(m==0) {
        	for(int i=0;i<n;i++)
            {
                for(int j=0;j<n;j++)
                {
                    if(i!=j)
                   System.out.print("0"+" ");
                    else System.out.print("1"+" ");
                }
                System.out.println();
			}
		}else {
			SQUARE_MATRIX_MULTIPLY(m);
			for (int[] item : A) {
				for (int data : item) {
					System.out.print(data + " ");
				}
				System.out.println();
			}
		}

	}

	public static void SQUARE_MATRIX_MULTIPLY(int m) {
		int n = A.length;
		m -= 1;
		
		while (m > 0) {
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < n; j++) {
					for (int k = 0; k < n; k++) {
						C[i][j] += B[i][k] * A[k][j];
					}
				}
			}
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < n; j++) {
					A[i][j] = C[i][j];
					C[i][j] = 0;
				}
			}
			m--;
		}
	}