C Programming - Declarations and Initializations - Discussion
Discussion Forum : Declarations and Initializations - General Questions (Q.No. 8)
8.
Is the following statement a declaration or definition?
extern int i;
extern int i;
Answer: Option
Explanation:
Declaring is the way a programmer tells the compiler to expect a particular type, be it a variable, class/struct/union type, a function type (prototype) or a particular object instance. (ie. extern int i)
Declaration never reserves any space for the variable or instance in the program's memory; it simply a "hint" to the compiler that a use of the variable or instance is expected in the program. This hinting is technically called "forward reference".
Discussion:
38 comments Page 2 of 4.
Wikiok said:
1 decade ago
Declaration: no memory is used. You can not declare a non user defined data type: "int a" is a definition. But you can declare any user defined data type: "struct mystruct{int a; };" It hasn't use any memory. In this view function prototypes are declarations too. "void myfunction(int a);"
Definition: Memory has been used in code or data segment. "int a;" "struct mystruct myvariable;" void myfunction(int a) {printf("%d",a); }
Definition: Memory has been used in code or data segment. "int a;" "struct mystruct myvariable;" void myfunction(int a) {printf("%d",a); }
Naveen Dahiya said:
1 decade ago
I am not agree with Wikiok.
We also can not declare a user defined data type like any structure or union because the memory is also allocated to these (structures or unions) in the same way as it is assigned to any int or float variable.
We also can not declare a user defined data type like any structure or union because the memory is also allocated to these (structures or unions) in the same way as it is assigned to any int or float variable.
Venky said:
1 decade ago
Let's consider file name is a1.c :
#include<stdio.h>
{
int i=10;
}
Then let us consider another file a2.c :
#include"a1.c"
#include<stdio.h>
main()
{
extern int i;
printf("%d\n",i);
}
Now this will print output is 10.
This is the right way how to use extern keyword.
#include<stdio.h>
{
int i=10;
}
Then let us consider another file a2.c :
#include"a1.c"
#include<stdio.h>
main()
{
extern int i;
printf("%d\n",i);
}
Now this will print output is 10.
This is the right way how to use extern keyword.
Devendra said:
1 decade ago
What is meaning of prototype?
Pri said:
1 decade ago
It means some rules and regulations.
Janani said:
1 decade ago
main()
{
extern int i;
i=20;
printf("%d",sizeof(i));
}
Output is error .please explain
{
extern int i;
i=20;
printf("%d",sizeof(i));
}
Output is error .please explain
Priya said:
1 decade ago
What is the difference between declaration and definition?
Princydhas said:
1 decade ago
int i=1;
This statement is definition or declaration ?
This statement is definition or declaration ?
Geetha said:
1 decade ago
Hey,whetr int i; is declaration or definition.
Dn, extern int i; is declaration or definition
Dn, extern int i; is declaration or definition
Siji said:
1 decade ago
Whtr int i; is declaration or definition.
Dn external int i; is declaration or definition
Int i=10; is declaration or definition
External int i=10; is declaration or definition
Dn external int i; is declaration or definition
Int i=10; is declaration or definition
External int i=10; is declaration or definition
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