New出来的区域必须Delete释放
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New出来的区域必须Delete释放
int * p = new int;
*p = 100;
声明一个新的整数类型区域 赋值
delete p;
new出来必须通过delete释放
用new申请的空间要用delete来释放
#include <iostream>
using namespace std;
int main()
{
//int a = 10;
//float b = 9.7f;
//int c = 20;
// & 取得一个变量的内存地址
//cout << &a << endl; // 0093F748
//cout << &b << endl; // 0093F73C
// * 从内存地址所对应的内存处 取得数据
//cout << *(&a) << endl; // 10
//cout << a << endl; // 10
// error： cout << *a << endl;
//int* pa = &a;
//float* pb = &b;
//cout << pa << endl; // 0079F722
//cout << pb << endl; // 0079F71C
//cout << *pa << endl; // 10
//cout << *pb << endl; // 9.7
//int* p;
//p = pa;
//cout << *p << endl; // 10
//cout << *pa << endl; // 10
//*pa = 100;
//cout << a << " " << *pa << endl; // 100 100
//*p = 300;
//cout << a << " " << *pa << " " << *p << endl; // 300 300 300
//int* p1 = NULL;
//int* p2 = 0;
//int* p3 = nullptr; // C++11
//cout << p1 << " " << p2 << " " << p3 << endl;;// 00000000 00000000 00000000
// 笔记：void 返回类型/任意类型指针
//void* p; // p 可以接收任意类型的指针
//p = &a;
////p = &b;
//cout << *((int*)p)<< endl; // 10
//int* p = new int;
//cout << *p << endl; // -842150451，没初始值
int* p = new int;
*p = 100;
cout << *p << endl; // 100
delete p; // 释放内存空间，通过new申请的，需要用delete释放
return 0;
}
