Multiple inheritance C++ program to convert a decimal number into binary

Write a program in C++ to convert a decimal number into binary without using the multiple inheritances.

#include<iostream>
using namespace std;
class decimal2binaryconversion1 
{
	public:
		long int i=0;
	};
	class decimal2binaryconversion2
	{
		public:
			char decnum[1000];
		};
	class child : public decimal2binaryconversion1 ,public decimal2binaryconversion2
	 {
	 public:
		int decimal2binary()
		{
			cout<<"Enter any decimal number:\n";
			cin>>decnum;
			cout<<endl;
			cout<<"binary value of "<<decnum<<" is ";
			while(decnum[i])
			{
				switch(decnum[i])
				{
				    	case'0':cout<<"000";
					break;
						case'1':cout<<"001";
					break;
						case'2':cout<<"010";
					break;
						case'3':cout<<"011";
					break;
						case'4':cout<<"100";
					break;
						case'5':cout<<"101";
					break;
						case'6':cout<<"110";
					break;
						case'7':cout<<"111";
					break;
						case'8':cout<<"000";
					break;
						case'9':cout<<"001";
					break;
					default:cout<<"invalid decimal number"<<decnum[i];
					break;
				}
				i++;
				cout<<endl<<endl<<endl;
			}
		}
	};
	int main()
     {
     	child myobject;
     	myobject.decimal2binary();
     	 }