I had this similar problem in a coding competition and this is how I handled it. Setting a precision of 2 to all double values
First adding the header to use setprecision
#include <iomanip>
Then adding the following code in our main
double answer=5.9999;
double answer2=5.0000;
cout<<setprecision(2)<<fixed;
cout <<answer << endl;
cout <<answer2 << endl;
Output:
5.99
5.00
You need to use fixed for writing 5.00 thats why,your output won't come for 5.00.