A program in C++ to create a Class Octal to perform decimal to octal conversion and addition of an octal and an interger by overloading ‘+’ and ‘=’.

#include<iostream.h>

#include<conio.h>

class octal

{private:int ov;

 public:octal()

            {ov=0;}

            void getdata();

            void octcon(int);

            octal operator=(int a);

            int operator+(int a);

            void showdata(int iv,int x)

            {cout<<"\n the decimal number:";

             cout<<iv;

             cout<<"\n the sum:"<<ov;

             getch();

            }

            void showdata(int iv)

            {cout<<"\n the octal number:";

             cout<<ov;

             cout<<"\n the decimal number:";

             cout<<iv;

             getch();

            }

}n1,n2;

void octal :: getdata()

{int x=0,i=0,temp,c=0;

 cout<<"\n for addition \n";

 while(x!=1)

 {temp=0;i=0;c=0;

  cout<<"\n enter octal number to be added:";

  cin>>ov;

  temp=ov;

  while(i==0)

  {if((temp%10)>7)

   {c++;}

   temp=temp/10;

   if(temp==0)

   {i=1;}

  }

  if(c!=0)

  {cout<<"\n invalid value enter again \n";

  }

  if(c==0)

  {x=1;}

 }

}

int octal :: operator+(int v)

{int c=0,l,k=1,temp;

 temp=ov;

 while(temp!=0)

 {l=temp%10;

  l=l*k;

  c=c+l;

  temp=temp/10;

  k=k*8;

 }

 temp=c+v;

 return temp;

}

octal octal:: operator=(int iv)

{int r=0,i=0,j,l,k,temp;

 temp=iv;

 while(temp!=0)

 {k=1;

  for(j=0;j<i;j++)

  {k=k*10;}

  l=temp%8;

  temp=temp/8;

  r=k*l+r;

  i++;

 }

 ov=r;

}

void octal :: octcon(int iv)

{int r=0,i=0,j,l,k,temp;

 temp=iv;

 while(temp!=0)

 {k=1;

  for(j=0;j<i;j++)

  {k=k*10;}

  l=temp%8;

  temp=temp/8;

  r=k*l+r;

  i++;

 }

 ov=r;

}

void main()

{int c=0,k=0,v;

 clrscr();

 while(k==0)

 {clrscr();

  cout<<"\n enter the choice of operation to be performed \n1-conversion of decimal to octal \n2-addition of an octal and an integer \n3-exit\n \n enter choice:";

  cin>>c;

  switch(c)

  {case 1:cout<<"\n enter the integer value to be converted:";

              cin>>v;

              n1.octcon(v);

              n1.showdata(v);

              break;

   case 2:n1.getdata();

              cout<<"\n enter the integer value to be added:";

              cin>>v;

              n2=n1+v;

              n2.showdata(v,0);

              break;

   case 3:k=1;

              cout<<"\n thanks for using the program";

              break;

   default:cout<<"\n you have entered wrong choice try again";

               getch();

  }

 }

 getch();

}