Float vars doubt

Hello guys!!! I have a doubt:

If I create a float variable:

//first command
float n = 2.59f;

//second command
float n = 2.59;

In one command, there is the letter "f" next the number... but the two commands work equal. What the difference between they?

Thank you!

Silas Justiniano - Brazil.

2.59 by default is a double by putting the f there you are saying that the literal is a float.