string构造函数
代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string s1;cout << "s1 = " << s1 << endl;const char *str = "hello world";string s2(str);cout << "s2 = " << s2 << endl;string s3(s2);cout << "s3 = " << s3 << endl;string s4(10, 'a');cout << "s4 = " << s4 << endl;}int main()
{test01();return 0;
}

测试结果:

总结:
string的多种构造方式没有可比性，灵活使用即可。

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string str1;str1 = "hello world";cout << "str1 = " << str1 << endl;string str2;str2 = str1;cout << str2 << endl;string str3;str3 = 'a';cout << "str3 = " << str3 << endl;string str4;str4.assign("hello c++");cout << "str4 = " << str4 << endl;string str5;str5.assign("hello c++", 5);cout << "str5 = " << str5 << endl;string str6;str6.assign(str5);cout << "str6 = " << str6 << endl;}int main()
{test01();return 0;
}

测试结果:

总结:
string的赋值方式很多，operator= 这种方式是比较实用的。

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string str1 = "我";str1 += "爱玩游戏";cout << "str1 = " << str1 << endl;str1 += ":";cout << "str1 = " << str1 << endl;string str2 = "LoL DNF";str1 += str2;cout << "str1 = " << str1 << endl;string str3 = "I";str3.append("Love");//str3.append(str2);str3.append("game abcde", 4);str3.append(str2, 4, 3);//从下标4位置开始，截取3个字符，拼接到字符串末尾cout << "str3 = " << str3 << endl;}int main()
{test01();return 0;
}

测试结果:

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{//查找string str1 = "abcdefgde";int pos = str1.find("de");if (pos == -1){cout << "no find" << endl;}else cout << "pos = " << pos << endl;pos = str1.rfind("de");cout << "pos = " << pos << endl;}void test02()
{//替换string str1 = "abcdefgde";str1.replace(1, 3, "1111");cout << "str1 = " << str1 << endl;
}int main()
{test01();cout << "-----------------------------------"<<endl;test02();return 0;
}

测试结果:

总结:

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string s1 = "hello";string s2 = "aello";int ret = s1.compare(s2);if (ret == 0){cout << "s1 = s2" << endl;}else if (ret > 0){cout << "s1 > s2" << endl;}else{cout << "s1 < s2" << endl;}}int main()
{test01();return 0;
}

测试结果:

总结：
字符串对比主要是用于比较两个字符串是否相等，判断谁大谁小的意义并不是很大。

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string str = "hello world";for (int i = 0; i < str.size(); i++){cout << str[i] << " ";}cout << endl;for (int i = 0; i < str.size(); i++){cout << str.at(i) << " ";}cout << endl;//字符修改str[0] = 'x';str.at(1) = 'x';cout << str << endl;}int main()
{test01();return 0;
}

测试结果:

总结:
string字符串中单个字符存取有两种方式，利用[]或at

代码如下：

#include <iostream>
#include <string>
using namespace std;void test01()
{string str = "hello";str.insert(1, "111");cout << str << endl;str.erase(1, 3);cout << str << endl;}int main()
{test01();return 0;
}

测试结果：

总结:
插入和删除的起始下标都是从0开始

代码如下:

#include <iostream>
#include <string>
using namespace std;void test01()
{string str = "abcdefg";string subStr = str.substr(1, 3);cout << "subStr = " << subStr << endl;string email = "hello@sina.com";int pos = email.find("@");string username = email.substr(0, pos);cout << "username = " << username << endl;
}int main()
{test01();return 0;
}

测试结果: