c语言中求两个矩阵的乘积

1、

#include <stdio.h>

int main(void)
{
    int a[4][3] = {{2,5,4},{1,2,4},{5,3,2},{4,2,6}};
    int b[3][4] = {{2,1,6,2},{3,2,4,1},{5,2,1,2}};
    int i, j, k;
    int c[4][4] = {0};
    
    for (i = 0; i < 4; i++)
    {
        for (k = 0; k < 4; k++)
        {
            for (j = 0; j < 3; j++)
            {
                c[i][k] += a[i][j] * b[j][k];
            }
        }
    }
    
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("%d ", c[i][j]);
        }
        putchar('\n');
    }
    return 0;
} 

 ↓

#include <stdio.h>

int main(void)
{
    int a[4][3], b[3][4];
    int i, j;
    puts("please input the elements of 4 * 3 matrix.");
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 3; j++)
        {
            printf("a[%d][%d] =  ", i, j); scanf("%d", &a[i][j]);
         } 
    }
    
    puts("please input the elements of 3 * 4 matrix.");
    for (i = 0; i < 3; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("b[%d][%d] = ", i, j); scanf("%d", &b[i][j]);
        }
    }
    
    
    int k;
    int c[4][4] = {0};
    for (i = 0; i < 4; i++)
    {
        for (k = 0; k < 4; k++)
        {
            for (j = 0; j < 3; j++)
            {
                c[i][k] += a[i][j] * b[j][k];
            }
        }
    }
    puts("output the multiply of the two matrix.");
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("%d ", c[i][j]);
        }
        putchar('\n');
    }
    return 0;
}

↓ 

#include <stdio.h>

int main(void)
{
    int a[2][4], b[4][5];
    int i, j;
    puts("please input the elements of the 2 * 4 matrix");
    for (i = 0; i < 2; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("a[%d][%d] = ", i, j); scanf("%d", &a[i][j]);
        }
    }
    puts("please input the elements of the 4 * 5 matrix");
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 5; j++)
        {
            printf("b[%d][%d] = ", i, j); scanf("%d", &b[i][j]);
        }
    }
    int c[2][5] = {0};
    int k;
    for (i = 0; i < 2; i++)
    {
        for (k = 0; k < 5; k++)
        {
            for (j = 0; j < 4; j++)
            {
                c[i][k] += a[i][j] * b[j][k];
            }
        }
    }
    puts("output the multiply of the two matrix.");
    for (i = 0; i < 2; i++)
    {
        for (j = 0; j < 5; j++)
        {
            printf("%d ", c[i][j]);
        }
        putchar('\n');
    }
    return 0;
}