C++ Program For Call by Value and Return by Value

Program 1

// Function declaration and definition
#include<iostream>
#define clrscr() system("cls")
using namespace std;
int add(int a,int b); 
int main()
{
    clrscr();
    int a,b,c;  
    cout<<"Enter two number";
    cin>>a>>b;
    c=add(a,b);  //call by value
    cout<<"Additon is : "<<c;
    return 0;
}
int add(int a,int b)
{
        int c;
        c=a+b;
        return c;
}

Program 2

// Function declaration and definition
#include<iostream>
#define clrscr() system("cls")
using namespace std;
int reverse(int n);  
int main()
{
    int n,x;
    clrscr();
    cout<<"\nEnter a number";
    cin>>n;
    cout<<"\nIn Main value of n before calling: "<<n;
    x=reverse(n);
    cout<<"\nIn Main value of n after calling: "<<n;
    cout<<"\nReverse is : "<<x;
    if(x==n)
    cout<<"\n No is palindrom";
    else
    cout<<"\n No is not palindrom";

}
int reverse(int n)
{
      int r,s=0;
      cout<<"\nIn Function before loop value of n: "<<n;
      while(n!=0)
      {
         r=n%10;
        s=(s*10)+r;
        n=n/10;
      }
      cout<<"\nIn Function after loop value of n: "<<n;

      return (s);
}