typedef defines a new data type. So you can have:
typedef char* my_string;
typedef struct{
int member1;
int member2;
} my_struct;
So now you can declare variables with these new data types
my_string s;
my_struct x;
s = "welcome";
x.member1 = 10;
For enum, things are a bit different - consider the following examples:
enum Ranks {FIRST, SECOND};
int main()
{
int data = 20;
if (data == FIRST)
{
//do something
}
}
using typedef enum creates an alias for a type:
typedef enum Ranks {FIRST, SECOND} Order;
int main()
{
Order data = (Order)20; // Must cast to defined type to prevent error
if (data == FIRST)
{
//do something
}
}