C primer plus plus :指针（1）

//

//  main.cpp

//  point1

//

//  Created by 炒饭 on 2019/4/14.

//  Copyright © 2019 炒饭. All rights reserved.

//

//指针和变量值硬币的两面性

#include <iostream>

 

int main()

{

    // insert code here...

    using namespace std;

    int updates = 6;

    int * p_updates;

    p_updates = &updates;

    //指针的地址初始化

    int higgens = 5;

    int *pta= &higgens;

    

    int nights =1001;

    int *pt = new int;

    *pt = 1001;

    

    cout  << "nights value =";

    cout << nights << ": location " << &nights <<endl;

    cout <<"int ";

    cout << "value = "<< *pt << ": location = "<< pt << endl;

    delete pt;

    

    //new创建和释放指针数组

    //type_name *pointer_name = new type_name [num_elements];pointer_name指向第一个元素

    short * ps = new short [500];

    delete [] ps;

    //访问动态数组的方法，将指针变量作为数组名

    double * p3 = new double [3];

    p3[0]=0.2;

    p3[1]=0.5;

    p3[2]=0.8;

    cout << "p3[1] is "<< p3[1] << ".\n";

    p3 = p3+1;

    cout <<" Now p3[0] is "<< p3[0] <<" and " ;

    cout << "p3[1] is "<< p3[1] << ".\n";

    p3= p3-1;

    delete [] p3;

    //表示值1

    cout << "Value: updates = " << updates;

    cout << ", *p_updates = "<< *p_updates <<endl;

    //表示地址

    cout << "Adresses: &updates =" << &updates;

    cout << ", p_updates= "<< p_updates <<endl;

    //改变值

    *p_updates = *p_updates +1;

    cout << "Now updates = "<< updates << endl;

    

    std::cout << "Hello, World!\n";

    return 0;

}

实验结果：

nights value =1001: location 0x7ffeefbff51c

int value = 1001: location = 0x10280ca30

p3[1] is 0.5.

Now p3[0] is 0.5 and p3[1] is 0.8.

Value: updates = 6, *p_updates = 6

Adresses: &updates =0x7ffeefbff538, p_updates= 0x7ffeefbff538

Now updates = 7

Hello, World!

Program ended with exit code: 0