C malloc实现：动态申请二维数组

#include <stdio.h>
#include <stdlib.h>

int main()
{
	float **p[10] = NULL;
	int array = 4, col = 3;
		
	/* 申请4个行指针 */
	p = (float **)malloc(array * sizeof(float *));
	if (NULL == p)
	{
		printf("malloc fail\n");
		return -1;
	}
	
	/* 为每行申请空间 */
	for (int i = 0; i < array; i++)
	{
		p[i] = (float *)malloc(col * sizeof(float));
		if (NULL == p[i])
		{
			printf("malloc fail\n");
			return -1;
		}
	}
	
	/* 赋值 */
	for (int i = 0; i < array; i++)
	{
		for (int j = 0; j < col; j++)
		{
			p[i][j] = i + j + 5.23;
		}
	}
	/* 打印 */
	for (int i = 0; i < array; i++)
	{
		for (int j = 0; j < col; j++)
		{
			printf("%f ", p[i][j]);
		}
		printf("\n");
	}
	
	/* free */
	for (int i = 0; i < array; i++)
	{
		free(p[i]);
	}
	
	free(p);
	p = NULL;
}

编译：

g++ malloc_array.cpp -o malloc_array && ./malloc_array

运行：

5.230000 6.230000 7.230000 
6.230000 7.230000 8.230000 
7.230000 8.230000 9.230000 
8.230000 9.230000 10.230000