C Programming - Declarations and Initializations - Discussion
Discussion Forum : Declarations and Initializations - General Questions (Q.No. 10)
10.
In the following program where is the variable a getting defined and where it is getting declared?
#include<stdio.h>
int main()
{
extern int a;
printf("%d\n", a);
return 0;
}
int a=20;
Answer: Option
Explanation:
- During declaration we tell the datatype of the Variable.
- During definition the value is initialized.
Discussion:
46 comments Page 3 of 5.
Gaurav Bachhav said:
1 decade ago
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.
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.
Anjali agarwal said:
1 decade ago
What is extern? please explain me?
Ajit Darnal said:
1 decade ago
Definition int a=20 ; is outside the main, how it is possible ?
Anjan said:
1 decade ago
If int a=20; then is it int a is declaration and a=20 defination?
Please clear me.
Please clear me.
Md Alam said:
1 decade ago
Hi friends,
I am agreed with that Prathyusha say.
Here in the program please go through the question again. He was just asking where "a" is declared and where it is defined.
Whether "a" is normal integer or external integer not matters.
So, declaration is : extern int a;.
And definition is :int a=20;.
If it is suppose to be a program that I write and declare a extern () funtion within the main () and define the variable outside the main (). Then it will work or not?
I am agreed with that Prathyusha say.
Here in the program please go through the question again. He was just asking where "a" is declared and where it is defined.
Whether "a" is normal integer or external integer not matters.
So, declaration is : extern int a;.
And definition is :int a=20;.
If it is suppose to be a program that I write and declare a extern () funtion within the main () and define the variable outside the main (). Then it will work or not?
Pooja said:
1 decade ago
External variable is declared as:
extern <data_type> <var>;
It is present in another program and we are refering it.
So we have to define it outside the main().....
extern <data_type> <var>;
It is present in another program and we are refering it.
So we have to define it outside the main().....
Pawan Asati said:
1 decade ago
option A is correct because extern is a storage class so a is treated as global variable so it definition can be out of main we write.
Teja said:
1 decade ago
What is this extern function? How and where it can be used?
Santhosh said:
1 decade ago
Here declaration part is ok but where in case of definition that defined at out side of the main function so it will not be considered if we execute that code we will get garbage value.
Rathika.b said:
1 decade ago
Please give an real example for "extern" keyword; Then only we know that how it works.
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