Why debugging and running outputs are different in C++?

Question

I want to read ".text" file and convert string as double. In debug mode i can read text as 99,03 but in running mode i can read only 99. I can't understand how it would be? My converting code is below

   double a = std::stod(text)

Answer 1

std::stod is affected by locale.

#include <iostream>
#include <string>
#include <clocale>

int main(void){
    std::setlocale(LC_ALL, "C");

    std::string s{"99.03"}; 
    double d = std::stod( s );
    std::cout<< d << "\n";
    std::setlocale(LC_ALL, "de_DE.UTF-8"); // A locale installed on your machine.
    std::string s2{"99,03"};
    double d2 = std::stod( s2 );
    std::cout<< d2 << "\n";
}

You may get the result as following: ( tested on msvc and gcc 9.3.0 )

99.03
99.03

If you want std::cout also print comma as decimal separator, imbue is required. You may refer to this post .