Purpose of a “.f” appended to a number?

Question

I saw \"1/3.f\" in a program, and wondered what the \".f\" was for. So tried my own program:

#include
using namespace std;
int main()
{
              


        

Answer 1

The decimal point and the f have a different purpose so it is not really .f

You have to understand that in C and C++ everything is typed, including literals.

3 is a literal integer. 3. is a literal double 3.f is a literal float.

An IEEE float has less precision than a double. float uses only 32 bits, with a 23 bit mantissa and 9 bit exponent (including the sign bits of each).

double gives you more accuracy, but sometimes you do not need such accuracy (e.g. if you are doing calculations on figures that are only estimates in the first place) and that given by float will suffice, and if you are storing large numbers of them (eg processing a lot of time-series data) that can be more important than the accuracy.

Thus float is still a useful type.

You should not confuse this with the notation used by printf and equivalent statements.