I have 5 programs that works 100%

I need to integrate them in one code using this code in the main

```
int A;
cout<<" Enter Your Choice";
cout<<"1. Algorithm A .";
cout<<"2. Algorithm B .";
cout<<"3. Algorithm C";
cout<<"4. Algorithm D";
cout<<"5. Algorithm E";
cin>> A;
if(A==1)
{
//call Algorithm A
}
else
if(A==2)
{//call Algorithm B
}
else
if(A==3)
{
//call Algorithm C
}
else
if(A==4)
{//call Algorithm D
}
else
if(A==5)
{//call Algorithm E
}
How to Integrate all progrms in one and how to call it using C++?
mybe delete the main from each program, but each one in a class as a function create instance of the class in the main and call the function???
Can any one send me any sample code to solve this out .
Thanks
```