在C ++中使用c_str（）将字符串转换为双精度

Question

Is it not reccomended to convert a string in such way:

string input = "81.312";
double val = atof(input.c_str());

Answer 1

DO NOT use std::atof in C++. That doesn't check for input error.

Use std::stod . That checks for error also and throws exception accordingly.

Also, it takes std::string const & as argument. So you don't have to pass input.c_str() . Just do this:

double value = std::stod(input);

Answer 2

It is not wrong, but more right would be to use boost::lexical_cast.

You should also check if these tools handle NANs and INFs correctly.