Question

Write a C++ program test.cpp. The class should contain a protected int member variable var, which is initialized with an integer value between 1 and 50 in a constructor that takes an integer parameter. The class should contain a public member function called play that should print out a sequence of integers as a result of iteratively applying a math function f to the member variable var. The function f is defined as f(x) = (3x+1)/2 if x is odd and f(x) = x/2 if x is even.

Stop the iteration when the value 1 is reached.

Example: When var is 6, the play function's output sequence should be 6,3,5,8,4,2,1.

In the main function create an object of this class whose member var should be initialized with the first command-line argument to the program (i.e., argv[1]) and then call the play member function to output the corresponding sequence of integers. You can check whether the supplied first command-line argument is an integer between 1 and 50 in the main function.

A sample run should look like this...

$./test 6

6 3 5 8 4 2 1

Answer 1

Code:

#include<iostream>
#include<cstdlib>
using namespace std;
class test
{
   protected:
       int var; //protected member declaration
   public:
       test(int v) //parameterised constructor
       {
           var=v;
       }
       void play() //method play
       {
           while(1)
           {
               cout<<var<<" ";
               if(var==1) //if the value is break the loop
               {
                   break;
               }
               if(var%2==0) //if var is even or not
                   var=var/2;
               else //if var is odd
                   var=(3*var+1)/2;
           }
       }
};

int main(int argc,char *argv[])
{
   if(argc!=2) //Check for command line argument passed or not
   {
       cout<<"Usage: ./test {number between 1 to 50}";
   }
   else
   {
       int n=atoi(argv[1]);
       if(n>50||n<1) //Check for the input number is bounded between 1 and 50
       {
           cout<<"Usage: ./test {number between 1 to 50}";
       }  
       else
       {
           test t(n); //creating object to the class
           t.play(); //play method invocation
       }
   }
}

Sample i/o:

when argument 6 is passed.

When no argument is passed:

Explaination:
The class test was written as per the requirements. The sample i/o of different execution was presented for understanding.

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