CODEWITHSUNDEEP
javavariablestypesdeclaration
Lunar Cultist
Lunar Cultist

Reputation: 81

Why is a long written with an L

If I want to save a long variable, why do I have to write an L or l at the end of the value?

For example:

9_223_372
long v = 9_223_372L;

But if I save it:

long v = 9_223_372;

it's still a long variable. So why do I have to write L or l?

Upvotes: 1

Views: 1090

Answers (1)

Zabuzard
Zabuzard

Reputation: 25903

int literal

If you do not write it, Java will create it as int and from there cast to long:

long number = 10;
// Is the same as
long number = (long) 10;
// i.e.
int asInt = 10;
long number = (long) asInt;

This works as long as the number you are writing is an int and will fail if its not, for example a very high number:

// Fails, "integer number too large"
long number = 10_000_000_000_000_000;

With L (or l) you tell Java that this literal is a long and not an int in the first place. Which also gets rid of the unnecessary conversion:

long number = 10_000_000_000_000_000L;

Note

The same also works for floating numbers, when you want a float instead of a double, you add F (or f). Technically, you can also add D or d for a double, but a floating number literal is already double by default, so this is not needed:

float asFloat = 0.5F;
double asDouble = 0.5D;
double alreadyDoubleByDefault = 0.5;

By the way, please do not use l (small L), it gets easily confused with 1 (one).

Upvotes: 2

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