Question

Illustrate, by example, how a C++ struct may be passed as a parameter by value or by reference. Also, show how it can be returned from a function. Be thorough in your example and explain your code.

Answer 1

Solution:

Passing a structure as parameter by reference is just same as passing an integer as reference.

In the same way a structure can be returned if it is declared as a return type.

In the example I have created a structure called pointer with 2 attributes x and y.

I used a call by reference function to set the values of the structure point.

I also defined a function midPoint which takes 2 points(structure) as argument and returns the midpoint which is also of type point.

Code:

#include<iostream>

using namespace std;

//Creating a structure for point
struct point
{
        float x;
        float y;
};

//A fuction that uses call by reference to set values to the point
void setPoint(point &p);

//A function that returns midPoint of 2 points
point midPoint(point a,point b);

//Driver function
int main()
{
        //Declaring two points a and b
        point a,b;
        
        //Setting values to point a
        a.x=0;
        b.y=0;
        
        //Call by reference to set values to the point B
        setPoint(b);
        
        //Creating a  Point for midpoint
        point m;
        m=midPoint(a,b);
        
        //Printing the details
        cout<<"Point a ("<<a.x<<","<<a.y<<")"<<endl;
        cout<<"Point b ("<<b.x<<","<<b.y<<")"<<endl;
        cout<<"MidPoint ("<<m.x<<","<<m.y<<")"<<endl;
        
        
}

void setPoint(point &p)
{
        cout<<"Enter value of x and y : ";
        cin>>p.x;
        cin>>p.y;
}

point midPoint(point a,point b)
{
        point m;
        m.x=(a.x+b.x)/2;
        m.y=(a.y+b.y)/2;
        
        return m;
}

Output: