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Why is this code invalid?
typedef int INT;
unsigned INT a=6;
whereas the following code is valid
typedef int INT;
static INT a=1;
?
As per my understanding unsigned int is not a "simple type specifier" and so the code is ill-formed. I am not sure though.
Can anyone point to the relevant section of the Standard which makes the first code invalid(and the second code valid)?
EDIT
Although Johannes Schaub's answer seemed to be correct and to the point(he had deleted his answer BTW) I accepted James Curran's answer for its correctness and preciseness.
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typedef is used to define new data type names to make a program more readable to the programmer. For example: | main() | main() { | { int money; | typedef int Pounds; money = 2; | Pounds money = 2 } | } These examples are EXACTLY the same to the compiler.
typedef is a reserved keyword in the programming languages C and C++. It is used to create an additional name (alias) for another data type, but does not create a new type, except in the obscure case of a qualified typedef of an array type where the typedef qualifiers are transferred to the array element type.
The typedef keyword allows the programmer to create new names for types such as int or, more commonly in C++, templated types--it literally stands for "type definition". Typedefs can be used both to provide more clarity to your code and to make it easier to make changes to the underlying data types that you use.
A typedef declaration is a declaration with typedef as the storage class. The declarator becomes a new type. You can use typedef declarations to construct shorter or more meaningful names for types already defined by C or for types that you have declared.
typedefs are not like macros. They are not just text substitution. A Typedef creates a new typename.
Now when you say unsigned int, the unsigned isn't a modifier which is tacked onto the int. unsigned int is the complete typename; it just happens to have a space in it.
So, when you say typedef int INT; then INT is the complete typename. It can't be modified.
static (like const) is a storage class specifier. It's not actually part of the type name.
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