How to Convert Numbers to words

Currently I'm attempting to convert a number to a word, but I'm unable to get the result that I want. Basically, my question is if I can convert a double to a string, the number converted into words, one for each decimal number, including the decimal points.

This is my method

String numberInWords (double numbers){
    String result = "" + numbers;
    for (int i = 0; i < result.length(); i++) {
        if( i == 0) {
            result += "zero";
        }
        if(i == 1) {
            result += "one";
        }
        if(i == 2) {
            result += "two";
        }
        if(i == 3) {
            result += "three";
        }
        if(i == 4) {
            result += "four";
        }
        if(i == 5) {
            result += "five";
        }
        if(i == 6) {
            result += "six";
        }
        if(i == 7) {
            result += "seven";
        }
        if(i == 8) {
            result += "eight";
        }
        if(i == 9) {
            result += "nine";
        }
    }
   return result;

}

and the result :

Expected :two three
Actual   :23.0zeroonetwothreefourfivesixseveneightnine

There are much more elegant ways to have this done, but I did it in a way that affects your code the least.

So, if you really want to have a double as an input, you will also want to enable to have 23L being printed as "two three point zero" because it is 23.0, if not, you can tweak my snippet, but that is what it will provide for you.

    String numberInWords (double numbers){
char[] numberInCharacters = String.valueOf(numbers).toCharArray();
String result = "";
for (int i = 0; i < numberInCharacters.length; i++) {
if(i != 0) {
result += " ";
}
if( numberInCharacters[i] == '0') {
result += "zero";
}
else if(numberInCharacters[i] == '1') {
result += "one";
}
else if(numberInCharacters[i] == '2') {
result += "two";
}
else if(numberInCharacters[i] == '3') {
result += "three";
}
else if(numberInCharacters[i] == '4') {
result += "four";
}
else if(numberInCharacters[i] == '5') {
result += "five";
}
else if(numberInCharacters[i] == '6') {
result += "six";
}
else if(numberInCharacters[i] == '7') {
result += "seven";
}
else if(numberInCharacters[i] == '8') {
result += "eight";
}
else if(numberInCharacters[i] == '9') {
result += "nine";
}
else if (numberInCharacters[i] == '.') {
result += "point";
}
}
return result;
}

If you only want predecimal part then you can transform the double to int and lose the decimal part then continue with the process to stringify it.

Although the code provided by kiselica-aldin will work ok, it doesn't solve most of the issues. It will also add a bug, since the last whitespace is never removed.

I've left comments to explain parts of the code.

public String numberInWords (double numbers){
String numbersAsString = String.valueOf(numbers); // "" + numbers isn't the best way of doing it
StringBuilder result = new StringBuilder(); //string builder is better that string concatenation
//we can iterate through the char list directly, no need to iterate through numbers and then access the char[] every time
for (char digit : numbersAsString.toCharArray()) {
if( digit == '0') {
result.append("zero "); //adding a trailing space, since you want them separated
continue; //what is the point of doing the other if statements if we already have a result?
}
if( digit == '1') {
result.append("one ");
continue;
}
if( digit == '2') {
result.append("two ");
continue;
}
if( digit == '3') {
result.append("three ");
continue;
}
if( digit == '4') {
result.append("four ");
continue;
}
if( digit == '5') {
result.append("five ");
continue;
}
if( digit == '6') {
result.append("six ");
continue;
}
if( digit == '7') {
result.append("seven ");
continue;
}
if( digit == '8') {
result.append("eight ");
continue;
}
if( digit == '9') {
result.append("nine ");
continue;
}
if( digit == '.') {
result.append("dot "); //or comma, or whatever, since there is a big difference between 1.25 and 125
//nothing to continue since it already is the last one
}
}
return result.toString().trim(); //trim to remove the last space
}