All you have to do is use a float (or double) for the variable.
Code:#include <iostream>
#include <stdlib.h>
using namespace std;
float decimal_num; //or you can use double
int main()
{
cout << "Enter any decimal number" << endl;
cin >> decimal_num;
cout << "You decimal number is " << decimal_num << endl;
system("PAUSE");
return 0;
}