Nothing, because it won't compile. Unless you mean "compiler output", in which case: errors.
Int is not a valid type (C++ is case sensitive so "int" does not mean the same as "Int")
l (lowercase L) is not defined so this will also throw an error.
Also there is a semicolon missing after the ++.
If the errors are fixed (and l really means n), then the output will be 1,2,3,... until n<0, which will be when the most significant bit of n is 1, which depends on sizeof(int). If int is four bytes on your system, the loop will terminate when n=0x80000000.