simple

Code:

void

Code:

 main()
{
extern char a[30];
}

How much array a is reserving memory space? how?

Why to use extern?
What is extern?

Also the void is not clear why you wrote it... I do not believe that you wanted to write

Code:

void main()

because the right thing is

Code:

int main(void)

and you want to do the right thing

As for the array, when we declare

Code:

char a[30]

we create space for 30 characters

Originally Posted by amzc

How much array a is reserving memory space? how?

Since char takes only one byte, a[30] reserves exactly 30 bytes.