Question

Solve this in c++ must read question carefully take one value only i think so,,,,,, otherwise you know better need solution urgently............

Write a program that pass two parameters to a function one by value and one by reference. Then check the original values whether their values have been changed or not.

Answer 1

• Theory of pass-by-value and pass-by-reference:
  • In pass-by-value method, when the function takes the argument,, it maked a copy of the argument and does operations on this copy. Any changes made to the copy will not be reflected on the original variable
  • In pass-by-reference method, when the funciton takes the argument, it takes a reference to this variable. Any changes made to the variable in the function will be reflected in the same variable in the calling function. pass-by-reference parameters are explicitly mentioned in the parameter list using & symbol after the datatype of the variable.
• In this program, we have demonstrate these two methods using a single fucntion call. This function will be taking two varaibles, one passed by value and another passed by reference.

program:

#include <iostream>

using namespace std;

void changeValues(int x, int& y){
   x += 5;
   y += 5;
}

int main(){
   int x = 5, y = 5;
   cout<<"Original Values:\n";
   cout<<"x = "<<x<<endl;
   cout<<"y = "<<y<<endl;
   changeValues(x,y);
   cout<<"Values after modification:\n";
   cout<<"x(passed by value) = "<<x<<endl;
   cout<<"y(passed by reference) = "<<y<<endl;
   return 0;
}

• Note that x is being passed by value and y is being passed by reference. Any changes made to y in changeValues() will be reflected for y in main(). But, this wont happen for x.

output: