标准库标头 ＜string_view＞ (C++17)学习
此头文件是字符串库的一部分。本篇介绍string_view的基本用法。
函数 | |
| operator== | 以字典序比较两个字符串视图 (函数模板) |
| operator<< (C++17) | 进行字符串视图的流输出 (函数模板) |
| swap | 交换两个对象的值 (函数模板) |
范围访问 | |
| begincbegin (C++11)(C++14) | 返回指向容器或数组起始的迭代器 (函数模板) |
| endcend (C++11)(C++14) | 返回指向容器或数组结尾的迭代器 (函数模板) |
| rbegincrbegin (C++14) | 返回指向一个容器或数组的逆向迭代器 (函数模板) |
| rendcrend (C++14) | 返回容器或数组的逆向尾迭代器 (函数模板) |
| sizessize (C++17)(C++20) | 返回容器或数组的大小 (函数模板) |
| empty (C++17) | 检查容器是否为空 (函数模板) |
| data (C++17) | 获得指向底层数组的指针 (函数模板) |
示例代码：
#include <iomanip>
#include <iostream>
#include <string_view>
#include <cstring>//https://zh.cppreference.com/w/cpp/header/string_view#pragma warning(disable:4996)
//C4996 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.//C++17标准
int main()
{//operator<< example (C++17)进行字符串视图的流输出constexpr std::string_view s{ "abc" };constexpr int width{ 5 };// fill/left/right 属性保留不变直至被修改std::cout << std::setfill('-');std::cout << std::left;std::cout << '[' << std::setw(width) << s << "]\n";std::cout << '[' << std::setw(width) << s << "]\n";std::cout << std::right;std::cout << '[' << std::setw(width) << s << "]\n";// 每次调用后重置宽度std::cout << '[' << s << "]\n";//swap examplestd::string_view s1{ "first" };std::string_view s2{ "were" };std::cout << "s1===========" << s1 << "\n";std::cout << "s2===========" << s2 << "\n";s2.swap(s1);std::cout << "s1===========" << s1 << "\n";std::cout << "s2===========" << s2 << "\n";//operator== examplestd::cout << "(s1==s2)=============" << (s1 == s2) << "\n";const char* source = "123456789";char dest[20];strcpy_s(dest, 10, source);//numberOfElements等于字符串大小std::cout << dest << "*\n";//data examplestd::string_view s3{"hello world"};char a3[32] = {'\0'};const char* src = s3.data();std::cout << "src==========" << src << "\n";std::strcpy(a3, s3.data());std::cout << "s3===========" << s3 << "\n";std::cout << "a3===========" << a3 << "\n";//empty examplestd::cout << "s3.empty=====" << s3.empty() << "\n";//size examplestd::cout << "s3.size======" << s3.size() << "\n";//begin example//std::string_view::iterator it = s3.begin();auto begin = s3.begin();std::cout << "begin========" << *begin << "\n";//cbegin exampleauto cbegin = s3.cbegin();std::cout << "cbegin=======" << *cbegin << "\n";//end exampleauto end = s3.end();end--;std::cout << "end==========" << *end << "\n";//cend exampleauto cend = s3.cend();cend--;std::cout << "cend=========" << *cend << "\n";//begin,cbegin,end,cend是一样的都不能修改值//rbegin exampleauto rbegin = s3.rbegin();std::cout << "rbegin========" << *rbegin << "\n";//crbegin exampleauto crbegin = s3.crbegin();std::cout << "crbegin=======" << *crbegin << "\n";//rend exampleauto rend = s3.rend();rend--;std::cout << "rend==========" << *rend << "\n";//crend exampleauto crend = s3.crend();crend--;std::cout << "crend=========" << *crend << "\n";}运行结果：
参考：
标准库标头 <string_view> (C++17) - cppreference.com