C Programming - Declarations and Initializations - Discussion

It shows an error msg because extern are declared inside the function.

If int a=20; is definition, then what about if we say int a=20; is initialisation?

@Jyoti.

Here is the code.

#include <stdio.h>
int main()
{
int i,j,n;
printf("enter the num:");
scanf("%d",&n);
for(i = 1; i <= n; i++)
{
for(j = 1; j <=n-i ; j++ )
printf(" ");
for(j = 1; j <= i; j++)
printf("* ");
printf("\n");
}
return 0;
}

Absolutely option A is correct answer.

But, declaration is outside of the main function.

So, could you please explain more about that?

What is extern? please explain me?

In C there are two important concept declaration and definition.

Declaration:-It only defines the type of variable but does not
allocate any memory space.

Ex:- extern int i;//this is the only way of only declaring variable.

Definition:-It also defines the type of variable but in this case the memory is allocated to variable and also it is initialized(initialization is not mandatory].

Ex:- int i=10;

int i; //this is also definition as memory is allocated but for simplicity we call it as declaration.

I think option D is correct because we never put semicolon after function definition.

since int a=20; is in outside of the main() it is definition.

What is the program for this output?

          *
        *   *
      *   *   *
    *   *    *   *
  *   *    *   *   *

In this question the extern keyword is used inside the function which is prohibited.