• 1. 关键词
• 2. C++20及之后
• 3. C++20之前
  • 3.1. strutil.h
  • 3.2. strutil.cpp
  • 3.3. 测试代码
  • 3.4. 运行结果
  • 3.5. 源码地址

1. 关键词

C++ 字符串处理 starts_with ends_with std::string 跨平台

2. C++20及之后

C++20标准开始，STL已经提供了starts_with和ends_with函数，可以直接使用。在 <string>头文件中，可以直接作为字符串对象的成员函数使用。

官方API文档: https://en.cppreference.com/w/cpp/string/basic_string

3. C++20之前

C++20之前, STL本身不支持starts_with和ends_with的功能，开发者需要自己实现，可参考以下实现代码。

3.1. strutil.h

#include <string>
namespace cutl
{/*** @brief Check if a string starts with a given substring.** @param str the string to be checked.* @param start the substring to be checked.* @param ignoreCase whether to ignore case when comparing, default is false.* @return true if the string starts with the substring, false otherwise.*/bool starts_with(const std::string &str, const std::string &start, bool ignoreCase = false);/*** @brief Check if a string ends with a given substring.** @param str the string to be checked.* @param end the substring to be checked.* @param ignoreCase whether to ignore case when comparing, default is false.* @return true if the string ends with the substring, false otherwise.*/bool ends_with(const std::string &str, const std::string &end, bool ignoreCase = false);
} // namespace cutl

3.2. strutil.cpp

#include <cctype>
#include <algorithm>
#include "strutil.h"namespace cutl
{bool starts_with(const std::string &str, const std::string &start, bool ignoreCase){int srclen = str.size();int startlen = start.size();if (srclen < startlen){return false;}std::string temp = str.substr(0, startlen);if (ignoreCase){return to_lower(temp) == to_lower(start);}else{return temp == start;}}bool ends_with(const std::string &str, const std::string &end, bool ignoreCase){int srclen = str.size();int endlen = end.size();if (srclen < endlen){return false;}std::string temp = str.substr(srclen - endlen, endlen);if (ignoreCase){return to_lower(temp) == to_lower(end);}else{return temp == end;}}
} // namespace cutl

3.3. 测试代码

#include "common.hpp"
#include "strutil.h"void TestStartswithEndswith()
{PrintSubTitle("TestStartswithEndswith");std::string str1 = "Hello, world!";std::string str2 = "GOODBYE, WORLD!";std::cout << str1 << " start with hello : " << cutl::starts_with(str1, "hello") << std::endl;std::cout << str1 << " start with hello ignoreCase: " << cutl::starts_with(str1, "hello", true) << std::endl;std::cout << str2 << " end with world! : " << cutl::ends_with(str2, "world!") << std::endl;std::cout << str2 << " end with world! ignoreCase: " << cutl::ends_with(str2, "world!", true) << std::endl;
}

3.4. 运行结果

---------------------------------------TestStartswithEndswith---------------------------------------
Hello, world! start with hello : 0
Hello, world! start with hello ignoreCase: 1
GOODBYE, WORLD! end with world! : 0
GOODBYE, WORLD! end with world! ignoreCase: 1

3.5. 源码地址

更多详细代码，请查看本人写的C++ 通用工具库: common_util, 本项目已开源，代码简洁，且有详细的文档和Demo。