Extern Variable

Question

 

Comments

Options??

You want the output or just the explanation.

Answer 1

Output will be :

66

 warning: ‘a’ initialized and declared ‘extern’
 extern int a = 6;
 

Extern keyword is the way we can declare a variable without actually defining it. But here we are declaring the variable and initializing at the same time which means that the memory is being allocated, which again means that the definition of the variable is given.

Hence, the compiler will show the warning message though it will compile successfully.

Declaration: Memory is not allocated only the prototype is given, that is the type of the arguments, return type etc.

Definition: Memory is allocated.

Comments

According to me there should be Error because the external variable can only be defined/initialized only once in a file but they have done twice so why isn't there any Error ?

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extern int a = 6 ===> simply as int a=6;

when a global variable declared twice it is error, But if one of them is not initialized then compiler will ignore the complete line which has no initialization.

 

in global section :-

int a;

int a=10;

No problem

 

int a=10;

int a;

No Problem

 

int a=10;

int a = 5;

Error with note, multiple declaration of a variable

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Best Brother @shaik Doubt gone :)