C++ String去除头尾空格 实现trim()方法

虽然C++11的标准库中并没有提供trim()方法，但我们可以使用string的find_first_not_of,和find_last_not_of方法实现trim()

#include <iostream>#include <string>std::string& trim(std::string &);int main() {std::string str = " Hello World ";std::cout << str << " size:" << s.size() << std::endl;std::cout << trim(s) << " size:" << trim(s).size() << std::endl;return 0;}std::string& trim(std::string &s) {if (s.empty()) {return s;}s.erase(0,s.find_first_not_of(" "));s.erase(s.find_last_not_of(" ") + 1);return s;}