【C++】常用容器-string容器

1.string基本概念

2.string构造函数

#include <iostream>
using namespace std;//string容器
void test01()
{string s1;//创建空字符串，调用无参构造函数cout << "str1 = " << s1 << endl;//什么都不输出const char* str = "hello world";string s2(str); //c_string转换成了stringcout << "str2 = " << s2 << endl;string s3(s2); //调用拷贝构造函数cout << "str3 = " << s3 << endl;string s4(10, 'a'); //使用n个字符c初始化cout << "str4 = " << s4 << endl;
}
//*************************************
int main() {test01();//test02();//**************************************system("pause");return 0;
}

3.string赋值操作

#include <iostream>
using namespace std;void test01()
{string str1;str1 = "hello world";cout << "str1 = " << str1 << endl;string str2;str2 = str1;cout << "str2 = " << 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;string str7;str7.assign(5, 'x');cout << "str7 = " << str7 << endl;
}
//*************************************
int main() {test01();//test02();//**************************************system("pause");return 0;
}

4.string字符串拼接

#include <iostream>
using namespace std;//string字符串拼接
//函数原型：
// string& operator+=(const char* str);            //重载+=操作符
// string& operator+=(const char c);               //重载+=操作符
// string& operator+=(const string& str);          //重载+=操作符
// string& append(const char *s);                  //把字符串S连接到当前字符串结尾
// string& append(const char *s,int n);            //把字符串S的前n个字符串连接到当前字符串结尾
// string& append(const string &s);                //同operator+=(const string& str)
// string& append(const string &s, int pos, int n);//字符串S中从pos开始的n个字符连接到字符串结尾
//********************************************************************************************void test01()
{// string& operator+=(const char* str);   //重载+=操作符string str1 = "我";str1 += "爱陶子";cout << "str1 = " << str1 << endl;// string& operator+=(const char c);               //重载+=操作符str1 += '!';cout << "str1 = " << str1 << endl;// string& operator+=(const string& str);          //重载+=操作符string str2 = " Miss Tao!";str1 += str2;cout << "str1 = " << str1 << endl;// string& append(const char *s);                  //把字符串S连接到当前字符串结尾string str3 = "I";str3.append(" love ");cout << "str3 = " << str3 << endl;// string& append(const char *s,int n);            //把字符串S的前n个字符串连接到当前字符串结尾str3.append("Tao! taozi", 4);cout << "str3 = " << str3 << endl;// string& append(const string &s);                //同operator+=(const string& str)str3.append(str2);cout << "str3 = " << str3 << endl;// string& append(const string &s, int pos, int n);//字符串S中从pos开始的n个字符连接到字符串结尾str3.append(str2, 6, 4);cout << "str3 = " << str3 << endl;
}int main() {test01();//test02();//**************************************system("pause");return 0;
}

不知道再查就好啦

5.string查找和替换

#include <iostream>
using namespace std;//string字符串的查找和替换//查找
void test01()
{string str1 = "abcdefgde";//findint pos = str1.find("de");if (pos == -1){cout << "未找到" << endl;}else{cout << "pos = " << pos << endl;}//rfindpos = str1.rfind("de");cout << "pos = " << pos << endl;//find和rfind的区别//find从左往右查找   rfind从右往左查找
}//替换
void test02()
{string str1 = "abcdefgde";str1.replace(1, 3, "1111"); //把第1到3位全部移除，将1111全部插入cout << "str1 = " << str1 << endl;
}int main() {//test01();test02();//**************************************system("pause");return 0;
}

《查找》的结果

《替换》的结果

6.string字符串比较

#include <iostream>
using namespace std;//string字符串比较
void test01()
{string str1 = "hello";string str2 = "delao";int ret = str1.compare(str2);if (ret == 0){cout << "str1等于str2" << endl;}else if (ret > 0){cout << "str1大于str2" << endl;}else{cout << "str1小于str2" << endl;}
}
int main() {test01();//test02();//**************************************system("pause");return 0;
}

7.string字符存取

#include <iostream>
using namespace std;//string字符存取
void test01()
{string str = "hello";cout << "str = " << str << endl;//1、通过[]访问单个字符for (int i = 0; i < str.size(); i++){cout << str[i] << " ";}cout << endl;//通过at方式访问单个字符for (int i = 0; i < str.size(); i++){cout << str.at(i) << " ";}cout << endl;//修改单个字符str[0] = 'x';//xellocout << "str = " << str << endl;str.at(1) = 'x';//xxlocout << "str = " << str << endl;
}
int main() {test01();//test02();//**************************************system("pause");return 0;
}

8.string插入和删除

#include <iostream>
using namespace std;//字符串插入和删除
void test01()
{string str = "hello";//插入str.insert(1, "111");//h111ellocout << str << endl;//删除str.erase(1, 3); //从1号位置开始的3个字符cout << str << endl;}int main() {test01();//test02();//**************************************system("pause");return 0;
}

9.string子串

#include <iostream>
using namespace std;//string子串截取
void test01()
{string str = "123456";string subStr = str.substr(1, 3);cout << "subStr = " << subStr << endl;//实用例子-从邮箱名提取用户信息string email = "[e-mail]";int pos = email.find('@');string usrname = email.substr(0, pos);cout << "Name = " << usrname << endl;
}int main() {test01();//test02();//**************************************system("pause");return 0;
}