Storage Classes 3 (Extern)

Extern Storage Class :-

Default Value :-

• Default value of extern variable is zero (0).
• We can declare global as well as local.

Memory :-

• It stored in data section

Life :-

• Life of extern variable start when program is loaded and end when program is execution completed.

Scope :- 

• If we declare variable as global then all the file (which compile at a time) and function we can use easily.
• If we declare local then we can access within the function only.

Important Note :- 

                           Global variable default an extern storage classes.

                           Default the function are extern but not variable.

                           By using extern we give the information to variable that its declaration may be present in other file.

                           If declaration is not present in other file as well so it will give an error.