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;
extern int a is declaration, int a = 20 is the definition
int a = 20 is declaration, extern int a is the definition
int a = 20 is definition, a is not defined
a is declared, a is not defined
Answer: Option
Explanation:

- During declaration we tell the datatype of the Variable.

- During definition the value is initialized.

Discussion:
45 comments Page 1 of 5.

Shital said:   6 years ago
If int a=20; is definition, then what about if we say int a=20; is initialisation?
(1)

Ramya said:   8 years ago
Will you explain please?

Ajit Darnal said:   1 decade ago
Definition int a=20 ; is outside the main, how it is possible ?

Anjali agarwal said:   1 decade ago
What is extern? please explain me?

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.

Sunil Kumar said:   1 decade ago
I think option D is correct because we never put semicolon after function definition.

Shwetha said:   1 decade ago
since int a=20; is in outside of the main() it is definition.

Jyoti mishra said:   1 decade ago
What is the program for this output?

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

Ayush said:   10 years ago
In this question the extern keyword is used inside the function which is prohibited.

Somjit Nag said:   9 years ago
a is declared and defined as a global variable. There is no need for an extern here.

Extern is used when the same variable needs to be used across multiple files (compilation units to be more precise).


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