static char *upto20[]={"one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen","twenty"};

#include <iostream>
#include <iomanip>

using namespace std;

const char *int_to_word(int i);

int main()
{
    cout << "Test of int_to_word()" << endl << endl;
     cout << "  i : Returned value" << endl;
    cout << "----------------------" << endl;
    for (int i = -2; i < 23; i++) {
        cout << setw(3) <<  i << " : <" << int_to_word(i) << ">" << endl;
    }
    return 0;
}

const char *int_to_word(int i)
{
    static const char *upto20[22] = {
        "zero",
        "one"    , "two"      , "three"   , "four"    , "five"   ,
        "six"    , "seven"    , "eight"   , "nine"    , "ten"    ,
        "eleven" , "twelve"   , "thirteen", "fourteen", "fifteen",
        "sixteen", "seventeen", "eighteen", "nineteen", "twenty" ,
        "Out of Bounds"
    };
    if ((i < 0) || (i > 20)) {
        return upto20[21];
    }
    else {
        return upto20[i];
    }
}