c macro: where we can access a variable

WHERE WE CAN ACCESS A VARIABLE...

void main()

{

    int a=10;

    printf("%d\n",a);

    {

        int b=20;

        printf("%d,%d\n",a,b);

    }

 printf("%d,%d",a,b); /*error: b not accesible */

}

EXPALNATION:

A variable defined in a block can be accessed in that block and all its inner blocks (i.r., a variable defined in a block cannot be accessed in its outer block).It is called as the scope of a variable .