S001-AC.cc 517 Bytes
#include <iostream>
#include <string>

using namespace std;

void dec2bin(int a)
{
	string str;
	char c;
	do
	{
		str.insert(0,1,((a & 0x1) + 48));
		a >>= 1;
	}while(a);
	cout << str;
}

void dec2hex(int a)
{
	cout << uppercase << hex << a;
}

void dec2oct(int a)
{
	cout << uppercase << oct << a;
}
int main()
{
	while(1)
	{
		int a;
		cin >> a;
		if(cin.eof())
		{
			return 0;
		}
		cout << a << " = ";
		dec2bin(a);
		cout << ", ";
		dec2oct(a);
		cout << dec << ", ";
		dec2hex(a);
		cout << dec << endl;
	}

}