Why should we use literals in C#?

Question

In some C# code I have seen staments like this:

float someFloat = 57f;

I want to know why we should use literals like f in the above case?.

Answer 1

Mainly so the compiler knows exactly what we mean - in particular for overload resolution:

Foo(57f);

should that call Foo(int) / Foo(float) / Foo(decimal) ?

Actually, I don't like remembering things - an alternative is:

float someFloat = (float)57;

this is not a runtime cast - it is identical (at the IL level) to 57f. The only time it is subtly different is with decimals with extra precision:

decimal someDecimal = (decimal)57.0; // same as 57M, not 57.0M (scale is different)

Answer 2

The "f" above is a type suffix. This tells the compiler the exact type of the literal provided. This is used so the compiler can allocate the appropriate amount of storage (precision) for the literal. By default, floating point literals are given storage for a "double." If you add "f" as a suffix, the literal will only get the storage for a float, which will have less accuracy.

double d = 50.1234; // given double storage
double d = 50.1234f; // given float storage, which might lose precision compared to double

Answer 3

By default, a real numeric literal on the right-hand side of the assignment operator is treated as double. Therefore, to initialize a float variable use the suffix f or F, for example:

float x = 3.5F;

If you don't use the suffix in the previous declaration, you will get a compilation error because you are attempting to store a double value into a float variable.

From MSDN: float