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本帖最后由 这是她 于 2020-6-10 21:46 编辑
We are most dive when we are in love. ——John Updike
STL(标准模板库)
STL六大组件:容器、算法、迭代器、仿函数、适配器(配接器)、空间配置器
String
String 本质上是一个类,类内部封装了char *,管理这个字符串,是一个char*型的容器
char*是一个指针
特点:
string 类内部封装了很多成员方法
string管理char*所分配的内存,不用担心复制越界和取值越界等,由类内部进行负责
- #include<iostream>
- #include<string>
- using namespace std;
- void test1()
- {
- //string(); 创建一个空的字符串
- //string(const char* s); 使用字符串s初始化
- //string(const string& str); 使用一个string对象初始化另一个string对象
- //string(int n,char c); 使用n个字符c初始化
-
- string s1;
-
- const char * str = "花甲粉";
- string s2(str);
- cout << "s2 = " << s2 << endl;
-
- string s3(s2);
- cout << "s3 = " << s3 << endl;
-
- string s4(10,'h');
- cout << "s4 = " << s4 << endl;
- }
- void test2()
- {
- //string& opertor=(const char* s); char*类型字符串赋值给当前的字符串
- //string& opertor=(const string &s); 把字符串s赋给当前的字符串
- //string& operator=(char c); 字符赋值给当前的字符串
- //string& assgin(const char* s); 把字符串s赋给当前的字符串
- //string& assgin(const char* s,int n); 把字符串s的前n个字符赋给当前的字符串
- //string& assgin(const string &s); 把字符串s赋给当前字符串
- //string& assgin(int n,char c); 用n个字符c赋给当前字符串
-
- string str1;
- str1 = "bang";
- cout << "str1 = " << str1 << endl;
-
- string str2;
- str2 = str1;
- cout << "str2 = " << str2 << endl;
-
- string str3;
- str3 = 'h';
- cout << "str3 = " << str3 << endl;
-
- string str4;
- str4.assign("i love you!");
- cout << "str4 = " << str4 << endl;
-
- string str5;
- str5.assign("hello world!",5);
- cout << "str5 = " << str5 << endl;
-
- string str6;
- str6.assign(str5);
- cout << "str6 = " << str6 << endl;
-
- string str7;
- str7.assign(10,'i');
- cout << "str7 = " << str7 << endl;
- }
- void test3()
- {
- //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连接到当前的字符串结尾
- //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); 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
-
- string str1;
- str1 = "我";
- str1 += "想去草原";
- cout << "str1 = " << str1 << endl;
-
- str1 += '!';
- cout << "str1 = " << str1 << endl;
-
- string str2 = "吃烤全羊";
- str1 += str2;
- cout << "str1 = " << str1 << endl;
-
- string str3 = "i";
- str3.append(" love ");
- cout << "str3 = " << str3 << endl;
-
- str3.append("fishc.too",4);
- cout << "str3 = " << str3 << endl;
-
- str3.append(str2);
- cout << "str3 = " << str3 << endl;
-
- string str4 = "hhhhh";
- str3.append(str4,0,5);
- cout << "str3 = " << str3 << endl;
-
- }
- void test4()
- {
- //int find(const string& str,int pos = 0)const;
- string str1 = "Wishing you chear skies and wide eyes.";
-
- int pos = str1.find("you");
-
- if (pos == -1)
- {
- cout << "未找到字符串!!!" << endl;
- }
- else
- {
- cout << "找到字符串,pos = " << pos << endl;
- }
-
- //rfind 和 find区别
- //rfind 从右向左查找 find 从左向右查找
- pos = str1.rfind("wide");
-
- cout << "pos = " << pos << endl;
-
- //从 1号位置起,7个字符替换为1111
- str1.replace(1,7,"1111");
-
- cout << "str1 = " << str1 << endl;
- }
- void test5()
- {
- string str1 = "fishc";
- string str2 = "fisha";
-
- //int compare(const string &s) const;与字符串s比较
- //int compare(const string *s) const;与字符串s比较
- if (str1.compare(str2) == 0)
- {
- cout << "str1 = str2" << endl;
- }
- else if (str1.compare(str2) > 0)
- {
- cout << "str1 > str2" << endl;
- }
- else
- {
- cout << "str1 < str2" << endl;
- }
- }
- void test6()
- {
- string str1 = "hello";
-
- //char& operator[](int n); 通过[]方式取字符
- //通过[]访问单个字符
- for (int i = 0;i < str1.size();i++)
- {
- cout << str1[i] << " ";
- }
- cout << endl;
-
- //char& at(int n); 通过at方式获取字符
- //通过at方式访问单个字符
- for (int i = 0; i < str1.size(); i++)
- {
- cout << str1.at(i) << " ";
- }
- cout << endl;
-
- //修改单个字符
- str1[0] = 'x';
-
- cout << "str1 = " << str1 << endl;
-
- str1.at(1) = 'y';
-
- cout << "str1 = " << str1 << endl;
-
- }
- void test7()
- {
- string str1 = "hello";
-
- //插入
- //string& insert(int pos,const char* s); 插入字符串
- //string& insert(int pos,const string& str); 插入字符串
- str1.insert(1,"6666");
-
- cout << "str1 = " << str1 << endl;
-
- //删除
- //string& insert(int pos,int n,char c); 在指定位置插入n个字符c
- //string& insert(int pos,int n = npos); 删除从pos开始的n个字符
- str1.erase(1,3);
-
- cout << "str1 = " << str1 << endl;
- }
- void test8()
- {
- string str1 = "fishc";
-
- //从字符串中获取想要的子串
- //string substr(int pos = 0,int n = npos)const; 返回由pos开始的n个字符组成的字符串
- string sub1 = str1.substr(1,3);
-
- cout << "sub1 = " << sub1 << endl;
-
- }
- int main()
- {
- test1();
-
- test2();//string 赋值
-
- test3();//string 拼接
-
- test4();//string 查找和替换
- test5();//string 比较
- test6();//string 存取
- test7();//string 插入和删除
- test8();//string 求子串
-
- return 0;
- }
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