What is the Role and Placement of Typedef in Struct in C Programming?

[transgalactic]

first i create this structure :

struct album { 
  char *name; 
  char *artist; 
  int numTracks; 
}

if i want my variables not to be global
i can write this inside main:

struct album CD1, CD2, CD3;

or
"
typedef struct album Album;

... then inside main:

Album CD1, CD2, CD3; "

i can't understand this last part regarding where to write the typedef line

and what is the role of type of typedef?

 

[computerex]

typedef allows you to use different identifiers to reference data types.
ie.

typedef unsigned short USHORT
typedef unsigned long  ULONG
typedef unsigned int    UINT

int main()
{  
    USHORT myShort = 5;
    ULONG   myLong = 10;
    UINT     sum = myShort+myLong;
    return 0;
}

typedefs should be used before the procedure definitions.