C++ string类学习总结

　　C++字符串技术 string类

　 string对象在大多数应用中被用来消除对char*指针的使用，支持所期望的一些操作;

　　可以转换成char*,保持和现代代码的兼容性，还能自动处理内存管理;

　　一些string的实现采用了引用计数，带来了比基于char*的字符串更佳的性能。

　　大多数的编译器已经实现了C++标准的std::string类~

 C++ Code 

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/* stlstring.cpp
    C++字符串技术  string类
    string对象在大多数应用中被用来消除对char*指针的使用，支持所期望的一些操作;
    可以转换成char*,保持和现代代码的兼容性，还能自动处理内存管理;
    一些string的实现采用了引用计数，带来了比基于char*的字符串更佳的性能。
    大多数的编译器已经实现了C++标准的std::string类~
*/

#include <iostream>
#include <string>

using namespace std;

int main(void)
{
    //构造字符串，给字符串赋值
    string myString1("Michael Joessy!");
    string myString2(10, 'q');
    string myString3 = "Michael Jordan~";
    string myString4(myString1);
    string myString5 = myString3;

    cout << myString1 << endl;
    cout << myString2 << endl;
    cout << myString3 << endl;
    cout << myString4 << endl;
    cout << myString5 << endl;

    //字符串读入和读出
    //string::operator>>  string::operator<<    string::getline
    string str;
    //getline(cin, str, ' ');
    cout << str << endl;

    //字符串判断函数
    /*字符串判断为空函数*/
    string empString("");
    if (empString.empty())
    {
        cout << "empString is empty!" << endl;
    }
    /*字符串长度函数*/
    string testString = "1234567890";
    cout << testString << endl;
    cout << "testString length is " << testString.length() << endl;
    cout << "testString size is " << testString.size() << endl;
    testString.resize(5);
    cout << testString << endl;
    cout << "testString length is " << testString.length() << endl;
    cout << "testString size is " << testString.size() << endl;
    /*提示：length(）和size()的功能是一样的，size()是基于STL概念提出来的，而length()还是原来C语言的东西，
            为了更好地符合STL的编程概念，建议使用size()。
    */

    /*字符串指针函数*/
    string str1("023");
    cout << "str1 = " << str1 << endl;
    cout << "str1 = " << str1.c_str() << endl;      //c_str()返回字符串的指针

    //增加字符串成员
    string strAppend("Michael ");
    cout << strAppend << endl;
    char szTest[] = "Jackson";
    strAppend.append(szTest);
    cout << strAppend << endl;
    string strInsert = " great";
    strAppend.append(strInsert, 0, 6);
    cout << strAppend << endl;
    strAppend.append(strInsert.begin(), strInsert.end());
    cout << strAppend << endl;

    strAppend += " person";
    cout << strAppend << endl;

    strAppend.push_back('!');
    cout << strAppend << endl;

    //字符串比较函数
    /*关系运算符 == > >= < <=*/
    string strt1 = "Michael";
    string strt2 = "Michael";
    if (strt1 == strt2)
    {
        cout << "strt1 == strt2" << endl;
    }
    string strt3 = "Michael Joessy";
    if (strt3 >= strt1)
    {
        cout << "strt3 >= strt1" << endl;
    }
    /*compare*/
    if (strt1.compare(strt2) == 0)
    {
        cout << "strt1 == strt2" << endl;
    }
    if (strt3.compare(strt1) != 0)
    {
        cout << "strt3 != strt1" << endl;
    }

    //字符串查找
    string strfind("abcdefg");
    int nPos = 0;
    nPos = strfind.find('c');
    cout << "The char c pos is " << nPos << endl;
    char szArray[] = "def";
    nPos = strfind.find(szArray);
    cout << "The szArray[] pos is " << nPos << endl;
    char szArrayNone[] = "drf";
    nPos = strfind.find(szArrayNone);
    cout << "The szArrayNone[] pos is " << nPos << endl;

    nPos = strfind.rfind('c');
    cout << "The char c pos is " << nPos << endl;
    nPos = strfind.rfind(szArray);
    cout << "The szArray[] pos is " << nPos << endl;
    nPos = strfind.rfind(szArrayNone);
    cout << "The szArrayNone[] pos is " << nPos << endl;

    string strCha = "aaabbbcccdddeeefffggghhh";
    nPos = strCha.find_first_of('b');
    cout << "The find_first_of b pos is " << nPos << endl;
    nPos = strCha.find_first_not_of('b');
    cout << "The find_first_not_of b pos is " << nPos << endl;
    nPos = strCha.find_last_of('b');
    cout << "The find_last_of b pos is " << nPos << endl;
    nPos = strCha.find_last_not_of('b');
    cout << "The find_last_not_of b pos is " << nPos << endl;

    //字符串下标和字串函数
    string strSub = "Hello World!";
    cout << strSub << endl;
    char ch1 = strSub[6];
    char ch2 = strSub.at(11);
    strSub.at(11) = '~';
    cout << strSub << endl;
    strSub.assign("Hello Man!");
    cout << strSub << endl;

    cout << strSub.substr(6, 9) << endl;

    //字符串其它函数
    string strOrg = "Hello Hero!";
    cout << strOrg << endl;
    strOrg.insert(0, "At ");
    cout << strOrg << endl;
    cout << strOrg.capacity() << endl;
    cout << strOrg.size() << endl;
    strOrg.replace(0, 2, "Ha");
    cout << strOrg << endl;

    cin.get();
    return 0;
}