c语言中如何计算数组长度

int len = sizeof(array)/sizeof(array[0]);

#include<stdlib.h>

#include<stdio.h>

void main()

{

    int rows = 0;    //行数

    int columns = 0; //列数

    int arr[3][4] = {

            {1,3,5,7},

            {9,11,13,15},

            {17,19,21,23}

        };

    rows = sizeof(arr) / sizeof(arr[0]);

    columns = sizeof(arr[0]) / sizeof(arr[0][0]);

    printf("数组行数：%d  列数：%d  总元素个数：%d * %d = %d \n",rows,columns,rows,columns, rows*columns);

    for (int i = 0;i<rows;i++)

    {

        for (int j = 0;j<columns;j++)

        {

            printf("arr[%d][%d] = %d \n",i,j,arr[i][j] );

        }

        printf("\n");

    }

    system("pause");

}

/*

输出：

数组行数：3  列数：4  总元素个数：3 * 4 = 12

arr[0][0] = 1

arr[0][1] = 3

arr[0][2] = 5

arr[0][3] = 7

arr[1][0] = 9

arr[1][1] = 11

arr[1][2] = 13

arr[1][3] = 15

arr[2][0] = 17

arr[2][1] = 19

arr[2][2] = 21

arr[2][3] = 23

请按任意键继续. . .

*/