为什么在使用float时Java强制我添加f？

Question

I'm very new to programming. I have the following code:

float f = 18.45f;

this works fine. If I change that to:

float f = 18.45;

java saying this as error:

error: possible loss of precision

But its optional in terms of double . But in long again I'm facing the same problem.

Why does java forces me to do so, but not in case with double ?

Answer 1

In Java, 18.45 is a double data type which holds 64-bit. float data type can hold up to 32-bit only. Adding the extra f makes it a float (float literal).

See Primitive Data Types for more details.