当一个数字在 Java 中被认为是双精度时，为什么我们使用浮点数？

Question

Why we use float type to store a number eg 1.23 when it's considered as double?. If we have to store 1.23 as float we type :

float number = 1.23F;

Why we use 'F' when float type is used?

Answer 1

Here is a great explanation from " Learning Java ":

Floating-point literals are of type double unless they are suffixed with an f or F denoting that they are to be produced as a float value.

Besides that, here are the similarities and the differences between these two primitive types.

• Both float and double consider float-point numbers.

• The difference is the precision each of them gives you. Whereas the float type can give you "only" 6-7 significant decimal digits, the double goes as far as having 15. As Mirek commented, the memory they need is different as well - 4 and 8 bytes accordingly.

Hope this clears up the confusion!