C Programming - Declarations and Initializations - Discussion

What is difference between definition and declaration?

What about initializing and defining. ?

Hi tomson,
Declaration is
int a;
char b;
float c;
.....
Initialization is
a=10;
b='h';
c=1.2;

We can use both declaration and initialization at same time
int a=10;
char b='w';
......
I think so now u understand.
If you hav any other doubt ask me.

What is the difference between initializing and declaring?

#include<stdio.h>
int funcall(int,int);//function prototyping
void main()
{
int sum=0;
int a=10,b=30;
sum=funcall(a,b);
printf("\nsum is %d",sum);
}

int funcall(a,b) //function definition
{
int cal=a+b;
printf("\ncal=%d",cal);
return cal;
}

out put: 40


Sorry prathyusha ur output is wrong that is not 10, 30 is the anws.
We have not to declare a is must that is mandetory...
y b'case we already declaring function call dat is funcall(int,int)..
any how ur explaination is good...

Thank u mr.sundar

Prototype means we specifies the interface of that declared function. And we will use that function for coherent task.

What is the diffetence between function declaration and prototyping ?

Thank you for your feedback @sundar.

@Prathyusha

This type of prototype declaration requires only in old compilers. (TurboC under 16-bit DOS OS).

But in modern compilers this function prototyping is not required.
GCC, VC++, C#, etc.

#include<stdio.h>
int funcall(int,int);//function prototyping
void main()
{
int a,sum;
sum=funcall(10,20);
printf("sum is %d",sum);
}

int funcall(int a,int b)
{
int cal=a+b;
return cal;
}

Output: sum is 10

When compiler come across the statement: sum=funcall(10,20);
it wants to know wat type of value it will return.so at that time it will go and check whether function prototyping is given or not , to see the datatype of the parameter used by that function.

CORRECT ME IF I AM WRONG PLZ!...