how to convert a floating point into a string

Question

How to convert a floating point into a string and add the 2 decimals when the floating point is a round number. Currently I am using the following, but for round numbers, I would like to have the .00 added. Do I need to write my own routine for that?

float floatingNumber = 1.00;
string string;
ostringstream stream;

stream << floatingNumber;
string += stream.str(); // result is 1 not 1.00

Answer 1

You should set precision manually and use flag, that allows you to use fixed notation

setprecision fixed

stream << std::fixed << std::setprecision(2) << floatingNumber;

Answer 2

if you are using c++11, you can convert a float to std::string using std::to_string()

float f(0.5f);
std::string str = std::to_string(f);

Same thing using auto :

auto f(0.5f); // f is a float
auto str = std::to_string(f); // str is a std::string

However, you'll have to handle the precision manually.