Hi,
I have a question regarding the conversion of double to int. Considering
this little program:
#include <iostream>
using namespace std;
int main()
{
double a = 50.0;
double b = 48.7;
double c = a - b;
cout << c << endl;
cout << c * 10 << endl;
cout << static_cast<int>(c * 10) << endl;
return 0;
}
I get this result:
1.3
13
12 <--- why not 13?
1) I am aware I may touch here the problem of floating point
representation and that the 1.3 value - result of a subtraction - is not
exactly this one, but maybe 1.2999999... Is this the reason why the int
conversion transforms the "double" 13 into a "int" equal to 12 ?
2) How to avoid this problem ? I'd like to be sure to round this number
correctly (with a precision of 1/10th, 1/100th, etc...).
I have tried to find relevant information regarding this issue but did
not find a clear answer,
Many thanks in advance,
Eric
