Number 0...100 to Text

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;


int main()
{
    int number;
    cin >> number;
    int tens = number / 10;
    int ones = number % 10;

    string one_names[] = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
    string teens[] = { "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };
    string ten_names[] = { "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety" };

    if (number < 0 || number > 100) { cout << "invalid number" << endl; }
    else if (number >= 0 && number <= 9) { cout << one_names[number] << endl; }
    else if (number >= 10 && number <= 19) { cout << teens[number - 10] << endl; }
    else if (number >= 20 && number < 100)
    {
        if (ones == 0) { cout << ten_names[tens - 2] << endl; }
        else { cout << ten_names[tens - 2] << " " << one_names[ones] << endl; }
    }
    else { cout << "one hundred" << endl; }
    return 0;
}