Boost组件 lexical_cast

1.字符串转换为数值

#include <iostream>#include <boost/lexical_cast.hpp>int main(int argc, _TCHAR* argv[]){using boost::lexical_cast;int a = lexical_cast<int>("123");double b = lexical_cast<double>("1234.12");std::cout << a << std::endl;std::cout << b << std::endl;getchar();return 0;}

2.数值转换为字符串

#include<boost/lexical_cast.hpp>#include <string>#include <iostream>int main(){using std::string;const double d = 123.12;string s = boost::lexical_cast<string>(d);std::cout<<s<<std::endl;return 0;}

3.异常

   如果转换失败，则会有异常bad_lexical_cast抛出。该异常类是标准异常类bad_cast的子类。

#include<boost/lexical_cast.hpp>#include <iostream>int main(){using std::cout;using std::endl;int i;try{i = boost::lexical_cast<int>("abcd");}catch(boost::bad_lexical_cast&e){cout<<e.what()<<endl;return1;}cout<<i<<endl;return0;}

   显然“ abcd”并不能转换为一个int类型的数值，于是抛出异常，捕捉后输出“ badlexicalcast:source type value could not be interpreted as target”这样的信息。

4.注意事项

   lexical_cast依赖于字符流std::stringstream，其原理相当简单：把源类型读入到字符流中，再写到目标类型中，就大功告成。