C Programming - Declarations and Initializations - Discussion

@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.

Thank you for your feedback @sundar.

What is the diffetence between function declaration and prototyping ?

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

#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

If possible say what is "prototype" in explanation.

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 about initializing and defining. ?

What is difference between definition and declaration?

Declaration is the process of declaring the variable with some special name and its data-type,scope,memory storage etc. and definition is actually assining some value to that variable.

In case of function declaration is defining its prototype and declaration is code where we specify what the function actually does.

Examples:

case 1) variable

Variable Declaration:
int a,b[10];

Variable Definition:
a=1, b={1,2,3,....};


Function Declaration:
void display();

Function Definition:

void display()
{
printf("......");
}