#include <iostream>
#include <string>
using namespace std;
/**
Turn a digit into its English name
@param n an integer between 1 and 9
@return the name of n ("one" . . . "nine")
*/
string digit_name(int n)
{ if (n == 1) return "one";
if (n == 2) return "two";
if (n == 3) return "three";
if (n == 4) return "four";
if (n == 5) return "five";
if (n == 6) return "six";
if (n == 7) return "seven";
if (n == 8) return "eight";
if (n == 9) return "nine";
return "";
}
/**
Turn a number between 10 and 19 into its English name
@param n an integer between 10 and 19
@return the name of n ("ten" . . . "nineteen")
*/
string teen_name(int n)
{ if (n == 10) return "ten";
if (n == 11) return "eleven";
if (n == 12) return "twelve";
if (n == 13) return "thirteen";
if (n == 14) return "fourteen";
if (n == 15) return "fifteen";
if (n == 16) return "sixteen";
if (n == 17) return "seventeen";
if (n == 18) return "eighteen";
if (n == 19) return "nineteen";
return "";
}
/**
Give the English name of a multiple of 10
@param n an integer between 2 and 9
@return the name of 10 * n ("twenty" . . . "ninety")
*/
string tens_name(int n)
{ if (n == 2) return "twenty";
if (n == 3) return "thirty";
if (n == 4) return "forty";
if (n == 5) return "fifty";
if (n == 6) return "sixty";
if (n == 7) return "seventy";
if (n == 8) return "eighty";
if (n == 9) return "ninety";
return "";
}
/**
Turn a number into its English name
@param n a positive integer < 1,000,000
@return the name of n (e.g. "two hundred seventy four")
*/
string int_name(int n)
{ int c = n; /* the part that still needs to be converted */
string r; /* the return value */
if (c >= 1000)
{ r = int_name(c / 1000) + " thousand";
c = c % 1000;
}
if (c >= 100)
{ r = r + " " + digit_name(c / 100) + " hundred";
c = c % 100;
}
if (c >= 20)
{ r = r + " " + tens_name(c / 10);
c = c % 10;
}
if (c >= 10)
{ r = r + " " + teen_name(c);
c = 0;
}
if (c > 0)
r = r + " " + digit_name(c);
return r;
}
int main()
{ int n;
cout << "Please enter a positive integer: ";
cin >> n;
cout << int_name(n);
return 0;
}