C++ Programming - Functions - Discussion

D is the correct option. Because default values of parameters can be specified in both function prototype and function definition.

The defaults values have to be in function declaration in header file. The answer is wrong.

Answer should be D. Because we can mention default argument either in proto or in the definition. Default argument can be specified in prototype declaring even without knowing the argument's name i.e. identifier.

/* Example for C++ Function Prototype and C++ Function Definition */

#include<iostream.h>
#include<conio.h>
#include<stdlib.h>

int add(int, int); // function prototype
int subtract(int, int); // function prototype
int multiply(int, int); // function prototype
int divide(int, int); // function prototype

void main()
{
clrscr();
int a, b;
cout<<"Enter any two number: ";
cin>>a>>b;
cout<<"\nSummation = "<<add(a, b);
cout<<"\nSubtraction = "<<subtract(a, b);
cout<<"\nMultiplication = "<<multiply(a, b);
cout<<"\nDivision = "<<divide(a, b);
getch();
}

int add(int x, int y) // function definition
{
int res;
res = x + y;
return res;
}

int subtract(int x, int y) // function definition
{
int res;
res = x - y;
return res;
}

int multiply(int x, int y) // function definition
{
int res;
res = x * y;
return res;
}

int divide(int x, int y) // function definition
{
if(y==0)
{
cout<<"\n\nDivide by Zero Error..!!";
cout<<"\nPress any key to exit...";
getch();
exit(1);
}
else
{
int res;
res = x / y;
return res;
}
}

If you write function definition 1st before main. Then there is no need of function prototype declaration. Hence you have to write default argument in definition itself.

But if you write 1st prototype then it is suggested to write default arguments in prototype.

Correct Answer is D.

Default values can bbe specified either in function header or function prototype.

@Raghav.

There is not mentioned about overloaded function in question. So I agree with @Nidhi.

But both function prototype and function declaration have same arguments like.

void ret(int a, int b, int c=20) ;

void ret(int a, int b, int c=20)

So option D is correct or not. Anyone clarify me.

@Nidhi.

No if we write:

void ret(int a,int b,int c=20)
{
cout<<c<<endl;
}

It not as declare default value for another function which are overloaded, it will can set c = 20 for only this function. Hence optn will be "C".

How it is C ?