C++中的动态二维数组创建

1.已知维度的常规定义法
#include<iostream>
using namespace std;

void main()
{
int p[2][2];

p[0][0] = 5;
p[0][1] = 6;
p[1][0] = 7;
p[1][1] = 8;

cout<<
p[0][0]<<' '<<p[0][1]<<endl<<
p[1][0]<<' '<<p[1][1];

getchar();
}

2.未知低维度的指针定义法
#include<iostream>
using namespace std;

void main()
{
int i = 2;
int (*p)[2];
p = new int [i][2];

p[0][0] = 5;
p[0][1] = 6;
p[1][0] = 7;
p[1][1] = 8;

cout<<
p[0][0]<<' '<<p[0][1]<<endl<<
p[1][0]<<' '<<p[1][1];

delete [] p;

getchar();
}

 
3.未知低维度和高维度的二重指针定义法
#include<iostream>
using namespace std;

void main()
{
int i = 2;
int **p;
p = new int * [i];
p[0] = new int [i];
p[1] = new int [i];

p[0][0] = 5;
p[0][1] = 6;
p[1][0] = 7;
p[1][1] = 8;

cout<<
p[0][0]<<' '<<p[0][1]<<endl<<
p[1][0]<<' '<<p[1][1];

delete [] p[0];
delete [] p[1];
delete [] p;

getchar();
}