C typedef Questions

Question 1

#include<stdio.h> int main() {    typedef int i;    i a = 0;    printf("%d", a);    getchar();    return 0; }

Output: 0
There is no problem with the program. It simply creates a user defined type i and creates a variable a of type i.

Question 2

#include<stdio.h> int main() {   typedef int *i;   int j = 10;   i *a = &j;   printf("%d", **a);   getchar();   return 0; }

Output: Compiler Error -> Initialization with incompatible pointer type.
The line typedef int *i makes i as type int *. So, the declaration of a means a is pointer to a pointer. The Error message may be different on different compilers.

Question 3

#include<stdio.h> int main() {   typedef static int *i;   int j;   i a = &j;   printf("%d", *a);   getchar();   return 0; }

Output: Compiler Error -> Multiple Storage classes for a.
In C, typedef is considered as a storage class. The Error message may be different on different compilers.