There is no fundamental reason to disallow overloading of ?:. I just didn’t see the need to introduce the special case of overloading a ternary operator. Note that a function overloading expr1?expr2:expr3 would not be able to guarantee that only one of expr2 and expr3 was executed.

The main problem is that you are trying to overload functions that only differ in return type. So int area(int) is the same as float area(int). You should get an error like:
error C2556: ‘float area(int)’ : overloaded function differs only by return type from ‘int area(int)’
This is because each overloaded function must have a distinct formal parameter list.

So the overloading problem we can easily fix by using a float area(float), this also fixes the problem of type conversion (and possible loss of data.) Then combat the problem of unwanted type conversion in float area(int,int,int);//area of triangle, we also change the type of the parameter list to float. Then fix the s=(x+y+z)/3; to s=(x+y+z)/2; and other minor changes. This example should compile without warnings or errors:

#include <iostream>
#include <math.h>
using namespace std;

int area(int);//area of square
int area(int,int);//area of rectangle
float area(float);//area of circle
float area(float,float,float);//area of triangle

//area of square
int area(int a) {
return a*a;
}

//area of rectangle
int area(int l,int b) {
return l*b;
}

//area of circle
float area(float r) {
return float((3.14*r*r));
}

//area of triangle
float area(float x,float y,float z) {
float s;
s = (x + y + z) / 2; // Not three as you had!
return(sqrt(s*(s-x)*(s-y)*(s-z)));
}

void main() {
int a,b;
float c,d,e;

cout << “\nInput an integer for area of square:”;
cin >> a;
cout << “\narea=” << area(a);

cout << “\nInput two integers for area of rectangle:”;
cin >> a >> b;
cout << “\narea=” << area(a,b);

cout << “\nInput a float for area of circle:”;
cin >> c;
cout << “\narea=” << area(c);

cout << “\nInput three floats for area of triangle:”;
cin >> c >> d >> e;
cout << “\narea=” << area(c,d,e);
}

Tip: always try to make your example programs as complete as possible (even if its only for a test) as we did by adding some comment lines and some extra screen output. This will help you in debugging.

We hope that this example helps you!!

float area(int,int,int);//area of triangle
int area(int);//area of square
int area(int,int);//area of rectaangle
float area(int);//area of circle

float area(int x,int y,int z)
{
float s;
s=(x+y+z)/3;
return(sqrt(s*(s-x)*(s-y)*(s-z)));
}

int area(int a)
{
return a*a;
}

int area(int l,int b)
{
return l*b;
}

float area(int r)
{
return float((3.14*r*r));
}

void main()
{
int x,y,z,a,l,b,r;
float s;
cout>>x>>y>>z;
cout<<"\narea="<<area(x,y,z);
cout>>a;
cout<<"\narea="<<area(a);
cout>>l>>b;
cout<<"\narea="<<area(l,b);
cout>>r;
cout<<"\narea="<<area(r);
getch();
}

All the above "area" functions are different, right? pls explain this for me.