指针常量和常量指针的几种改变方式

// 常量指针

int const * p;

const int * p;

// 指针常量

int * const p;

#include <iostream>using namespace std;int main(){char str1[] = "123"; //程序运行前就分配的内存空间char str2[] = "123";cout << (str1 == str2) << endl; // 0, 两个字符数组分配的地址空间肯定不一样char *str3 = "123";char *str4 = "123";const char *str5 = "123"; cout << "str5= " << str5 << endl;  char const *str6 = "123";char * const str7 = "123";cout << (str3 == str4) << endl; // 1cout << (str3 == str5) << endl; // 1cout << (str3 == str6) << endl; // 1cout << (str3 == str7) << endl; // 1int a = 200;const int * ppt = &a;cout << "ppt= " << *ppt << endl;int b = 100;ppt = &b; //指针ppt本身的值可以改变cout << "ppt= " << *ppt << endl;//*ppt = b;int * const cht = &a;cout << "cht= " << *cht << endl;*cht = b; // cht指向的对象值可以改变cout << "cht= " << *cht << endl;int const* const thr = &a;cout << "thr= " << *thr << endl;a = 900;  // 通过改变a的值来改变thr指向对象的值cout << "thr= " << *thr << endl;return 0;}