Integer To English Words

Integer To English Words string

Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1.

``````For example,

123 -> "One Hundred Twenty Three"
12345 -> "Twelve Thousand Three Hundred Forty Five"
1234567 -> "One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven"
``````

Integer To English Words Solution

``````public class IntegerToEnglishWords {
private final String[] LESS_THAN_20 = { "", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
private final String[] TENS = { "", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };
private final String[] THOUSANDS = { "", "Thousand", "Million", "Billion" };

public String numberToWords(int num) {
if(num == 0) {
return "Zero";
}

int i = 0;
String words = "";

while(num > 0) {
if(num % 1000 != 0) {
words = helper(num % 1000) + THOUSANDS[i] + " " + words;
}

num /= 1000;
i++;
}

return words.trim();
}

private String helper(int num) {
if(num == 0) {
return "";
} else if(num < 20) {
return LESS_THAN_20[num] + " ";
} else if(num < 100) {
return TENS[num / 10] + " " + helper(num % 10);
} else {
return LESS_THAN_20[num / 100] + " Hundred " + helper(num % 100);
}
}
}``````