C++中动态申请二维数组

#include <iostream>

using namespace std;

void createArray(int size_m, int size_n)
{
	float **arr = new float *[size_m];
	for (int i = 0; i < size_m; i++)
	{
		arr[i] =new float[size_n];
		for (int j = 0; j <size_n; j++)
		{
			arr[i][j] = (float)((i + 1) * 10 + j + 1);
			cout<<arr[i][j]<<" ";
		}
		cout<<endl;
	}
        //释放内存空间
        for (int i = 0; i < size_m; i++)
	{
		delete [] arr[i];
	}
	delete [] arr;
}

int main()
{
	int size_m = 4;//行数
	int size_n = 5;//列数
	createArray(size_m, size_n);
	return 0;
}

#include <iostream>

using namespace std;

void createArray(int size_m, int size_n)
{
	float **arr = (float **)malloc(sizeof(float) * size_m);
	for (int i = 0; i < size_m; i++)
	{
		arr[i] = (float *)malloc(sizeof(float) * size_n);
		for (int j = 0; j <size_n; j++)
		{
			arr[i][j] = (float)((i + 1) * 10 + j + 1);
			cout<<arr[i][j]<<" ";
		}
		cout<<endl;
	}
	for (int i = 0; i < size_m; i++)
	{
		free(arr[i]);
	}
	free(arr);
}

int main()
{
	int size_m = 4;
	int size_n = 5;
	createArray(size_m, size_n);
	return 0;
}