The Storage Class register
The Storage Class register : The storage class 'register' tells the compiler that the associated variable should be stored in high-speed memory registers, provided it is physically and semantically possible to do so. This storage class defaults to automatic whenever the compiler cannot allocate an appropriate physical register. Basically, the use of storage class 'register' is an attempt to improve execution speed. An example id
void main()
{ register int i; Statements;
}
If a storage class is specified in a declaration and the type is absent, then the type is 'int' by default.
The declaration
register i; is equivalent to register int i;