c++ - 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 <iostream>

int main()
{
    std::cout << (float) 1/3 << std::endl;
    std::cout << 1/3.f << std::endl;
    std::cout << 1/3 << std::endl;
}

Is the .f used like a cast? Is there a place where I can read more about this interesting syntax?

Answer 1

3. is equivalent to 3.0, it's a double.

f following a number literal makes it a float.