How can I convert numbers to words in Java?

Converting Numbers to Words in Java

Introduction:

We often encounter scenarios where we need to convert numerical values into their corresponding word representations. In Java, there isn't a built-in function that directly performs this conversion. However, with a bit of custom code, we can develop a solution that caters to our requirements.

Custom Solution:

We can create a custom class that handles the conversion process. Let's break down the approach:

Step 1: Handling Small Numbers (0 to 99)

• Create an array containing names for numbers from 0 to 19 (numNames).
• To handle numbers like "twenty" and "thirty," create another array with tens' names (tensNames).

Step 2: Converting Two-Digit Numbers

• Divide the number by 100 to get the hundreds digit (hundreds).
• Modulus division by 100 gives us the remaining two digits (remainder).
• Get the hundreds digit's name from numNames.
• Use a loop to construct the word representation of the remaining two digits using numNames and tensNames.

Step 3: Converting Three-Digit Numbers

• Repeat the process for three-digit numbers.
• Divide by 1000 to get thousands (thousands), then perform modulus division to get the remaining three digits.
• Append the thousands digit's name from numNames and "thousand" to the result.

Step 4: Converting Larger Numbers

• Follow the same process for millions, billions, and so on.
• Divide the number by the appropriate power of 10 to extract the corresponding digit count.
• Modulus divide to get the remaining digits.
• Append the correct magnitude (e.g., "million", "billion") to the result.

Example Code:

This code demonstrates the custom solution:

import java.text.DecimalFormat;

public class EnglishNumberToWords {

  private static final String[] tensNames = {
    "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
  };

  private static final String[] numNames = {
    "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
    "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen",
    "seventeen", "eighteen", "nineteen"
  };

  private EnglishNumberToWords() {}

  private static String convertLessThanOneThousand(int number) {
    // Handle numbers between 0 and 99
    String soFar;
    if (number % 100 < 20){
      soFar = numNames[number % 100];
      number /= 100;
    }
    else {
      soFar = numNames[number % 10];
      number /= 10;
      soFar = tensNames[number % 10] + soFar;
      number /= 10;
    }
    if (number == 0) return soFar;
    return numNames[number] + " hundred" + soFar;
  }

  public static String convert(long number) {
    if (number == 0) { return "zero"; }
    String snumber = Long.toString(number);
    String mask = "000000000000";
    DecimalFormat df = new DecimalFormat(mask);
    snumber = df.format(number);
    // Handle billions, millions, hundred thousands, and thousands separately
    int billions  = Integer.parseInt(snumber.substring(0,3));
    int millions  = Integer.parseInt(snumber.substring(3,6));
    int hundredThousands = Integer.parseInt(snumber.substring(6,9));
    int thousands = Integer.parseInt(snumber.substring(9,12));
    String tradBillions;
    switch (billions) {
    case 0:
      tradBillions = "";
      break;
    case 1 :
      tradBillions = convertLessThanOneThousand(billions) + " billion ";
      break;
    default :
      tradBillions = convertLessThanOneThousand(billions) + " billion ";
    }
    String result =  tradBillions;
    String tradMillions;
    switch (millions) {
    case 0:
      tradMillions = "";
      break;
    case 1 :
      tradMillions = convertLessThanOneThousand(millions) + " million ";
      break;
    default :
      tradMillions = convertLessThanOneThousand(millions) + " million ";
    }
    result =  result + tradMillions;
    String tradHundredThousands;
    switch (hundredThousands) {
    case 0:
      tradHundredThousands = "";
      break;
    case 1 :
      tradHundredThousands = "one thousand ";
      break;
    default :
      tradHundredThousands = convertLessThanOneThousand(hundredThousands) + " thousand ";
    }
    result =  result + tradHundredThousands;
    String tradThousand;
    tradThousand = convertLessThanOneThousand(thousands);
    result =  result + tradThousand;
    return result.replaceAll("^\s+", "").replaceAll("\b\s{2,}\b", " ");
  }
}

Usage:

System.out.println(EnglishNumberToWords.convert(123456789));
// Output: "one hundred twenty three million four hundred fifty six thousand seven hundred eighty nine"

Conclusion:

With this custom solution, you can convert numerical values into their word representations easily and efficiently.

The above is the detailed content of How can I convert numbers to words in Java?. For more information, please follow other related articles on the PHP Chinese website!