C++对象内容比较和指针比较

使用容器存储的时候，一定要注意里面存储的是对象和还是对象的指针，这两者是有区别的。如果是对象的话，在进行一个删除、查找Find操作的时候，会调用类的比较==运算符，旨在内容的比较，而如果是指针的话，则会判断是否是指向的一个对象。给出演示代码如下：

#include <string>
#include <memory>
#include <vector>
#include <map>
#include <iostream>

using namespace std;

void test1()
{
    string  str1("abc");
    string  str2("123");
    string  str3("ABC");

    vector<string> vecStr;
    vecStr.push_back(str1);
    vecStr.push_back(str2);
    vecStr.push_back(str3);

    string  str4("ABC");
    //vector<string>::iterator it = vecStr.begin();
    //for (; it != vecStr.end(); it++)
    //{
    //    if ((*it) == str4)
    //    {
    //        cout << "target occurs in test1" << endl;
    //        break;
    //    }
    //}

    vector<string>::iterator result = find(vecStr.begin(), vecStr.end(), str4);
    if(result!= vecStr.end())
        cout << "target occurs in test1" << endl;
}

void test2() 
{
    string*  pStr1=new string("abc");
    string*  pStr2 = new string("123");
    string*  pStr3 = new string("ABC");

    vector<string*> vecStr;
    vecStr.push_back(pStr1);
    vecStr.push_back(pStr2);
    vecStr.push_back(pStr3);

    string*  pStr4 = new string("ABC");
    //vector<string*>::iterator it = vecStr.begin();
    //for (; it != vecStr.end(); it++)
    //{
    //    if ((*it) == pStr4)
    //    {
    //        cout << "target occurs in test2" << endl;
    //    }
    //}


    //compare1
    vector<string*>::iterator result = find(vecStr.begin(), vecStr.end(), pStr4);
    if (result != vecStr.end())
        cout << "target occurs in test2 compare1 method " << endl;

    //compare2
    vector<string*>::iterator it = vecStr.begin();
    for (; it != vecStr.end(); it++)
    {
        if (string(*(*it))==string(*pStr4))
        {
            cout << "target occurs in test2 compare2 method" << endl;
        }
    }

    delete pStr1;
    delete pStr2;
    delete pStr3;
    delete pStr4;
}


int main()
{
    cout << "begin test" << endl;
    test1();
    test2();

    return 0;
}