Does type conversion happen if assigning a number to a long type without postfix "L"

Question

My question is that if the following assignment in (1) involves type convernsion, i.e., from int to long?

(1)
    long i=0;
    ....
    i =2; 
(2)
    long i=0;
     .....
    i = 2L

This might be worth reading: http://en.cppreference.com/w/cpp/language/implicit_cast — shuttle87, Jul 02 '14 at 16:27
Also related: http://stackoverflow.com/questions/271076/what-is-the-difference-between-an-int-and-a-long-in-c — Marco A., Jul 02 '14 at 16:28

score 2 · Accepted Answer · answered Jul 02 '14 at 16:28

Yes, it involves conversion. But with a literal like this, the conversion will normally happen at compile time, so appending the L won't make any real difference unless you find the code more readable with the L there (I normally don't).

There are a few cases where you can append a suffix to get a result that's actually different from what you'd get without the suffix, but the ones you've shown don't fall into this category.

score 0 · Answer 2 · answered Jul 02 '14 at 16:32

Technically, yes, it's a conversion. The type of an integer literal without a suffix is int as long as the literal's value can indeed by represented by an int. This is certainly the case for the values 0 and 2. So, in i = 2, the right-hand side is int, and must be converted to long

However, it's only a conversion by the rules of the language. The compiler is undoubtedly going to generate code that directly sets the value of i to 2, rather than code that stores 2 in an int variable and then performs a run-time conversion.

Does type conversion happen if assigning a number to a long type without postfix "L"

2 Answers2