C Programming - Declarations and Initializations - Discussion

2 bytes is output according to programming code gives. And defined correction in correct and unsigned, signed int or long or short is correct.

But defined object is seen as interger and it 20=I is correct declared, so integer declared but written in outer side on scope.

@All.

According to me, the coding is;

#include<stdio.h>
int main()
{
extern int i;
printf("\n%d",sizeof(i));
return 0;
}
int i=20;

If you declare the extern int i; it will not allocate memory, when you define extern int i=0; it will allocate memory.

@All.

As per my knowledge;

is extern int a - local or global variable or something else? and also in answer int a=20 is referred as a local variable but it should be a global variable.

So what happens when there is a conflict when between extern and global variable defined below :
#include<stdio.h>
int main()
extern int a;
int a=20;
{

printf("%d\n", sizeof(a));
return 0;
}

I guess it should give priority to int a=20, but what will happen when there is no conflict who will get the preference extern int a OR int a=20?

So, the reason the program will show linkage error is:

-> extern int i; (which is an EXTERNAL LINKAGE is a declaration that says that there exists a variable 'i' in some other program but it does not define it in the current program.. the variable will come into existence only when it is defined in the program. Until then, it is virtually declared and does not exist in the program. Thus, it shows the error 'UNDEFINED SYMBOL 'i'.

#include<stdio.h>
int main()
{
extern int a;
printf("%d\n", sizeof(a));
return 0;
}

Please explain me the output.

When i am running like this no error is showing. why?

#include<stdio.h>
int main()
{
extern int i;
printf("%d\n", sizeof(i));
return 0;
}
i = 20;

Would you please explain why we get an error?

Is it because we have not kept single code for i?

Here, int i=20; is the definition.

int i=20; is this statement a declaration or definition?

Explain in detail.