C++11:string类的常用接口说明及其功能测试

C++11:string类的常用接口说明及其功能测试

string类对象的常见构造string类对象的容器操作string类对象的访问及其遍历操作string类对象的修改操作

测试代码

#define _CRT_SECURE_NO_WARNINGS 1 #include<iostream> #include<string> #include<functional> using namespace std; void fun(int n) { string str; str.reserve(100);//一次性预留空间，提升效率,减少扩容次数 for (int i = 0; i < n; ++i) { cout << "capacity = " << str.capacity() << endl; str.push_back('a'); } } int my_strlen(const char *str) { int count = 0; while (*str++ != '\0') { count++; } return count; } int main() { //字符串构造 string str1; cout << "str1 = " << str1 << endl; string str2("zxcvbnm"); cout << "str2 = " << str2 << endl; string str3(10, '#'); cout << "str3 = " << str3 << endl; string str4(str3); cout << "str4 = " << str4 << endl; //功能测试 cout << "size = " << str3.size() << endl;//求有效字符长度 cout << "length = " << str3.length() << endl;//字符串特有计算有效字符长度 cout << "capacity = " << str3.capacity() << endl;//字符串容量 str3 += "sadasdasdasda"; cout << "capacity = " << str3.capacity() << endl;//自动扩容 str3.clear(); cout << "size = " << str3.size() << endl; str2.resize(15, '+');//重新调整元素个数 cout << "str2 = " << str2 << endl; cout << "length = " << str2.length() << endl; cout << "capacity = " << str2.capacity() << endl; str2.resize(3, '+'); cout << "str2 = " << str2 << endl; str2.reserve(10);//调整预留容量 cout << "capacity = " << str2.capacity() << endl; str2.reserve(100); cout << "capacity = " << str2.capacity() << endl; //fun(100); for (unsigned int i = 0; i < str2.size(); ++i) { cout << str2[i]; } cout << endl; auto it = str2.begin(); while (it != str2.end()) { cout << *it; ++it; } cout<<endl; for (const auto &e : str2) cout << e; cout << endl; auto rit = str2.rbegin(); while (rit != str2.rend()) { cout << *rit; ++rit; } cout << endl; str2.push_back('H');//在字符串后插入字符 str2.append("xht");//追加字符串 str2 += "mad"; cout << str2 << endl; //C str 找到对象内部的指针将其类型强转为c类型的指针 cout << "str length = " << my_strlen(str2.c_str()) << endl; string str = "https://blog.csdn.net/qq_42613519"; //size_t pos = str.find('b'); //size_t pos = str.find("net"); size_t pos = str.rfind('4'); if (pos != string::npos) cout << "pos = " << pos << endl; else cout << "查找字符不存在" << endl; size_t start_pos = str.find('b'); size_t end_pos = str.find('9'); cout << "pos = " << end_pos << endl; string tmp_str = str.substr(start_pos, end_pos - start_pos + 1);//获取子串 cout << tmp_str << endl; system("pause"); return 0; }

测试结果（部分）