Program to convert a given number to words

Write code to convert a given number into words. For example, if “1234” is given as input, output should be “one thousand two hundred thirty four”.

Following is the implementation for the same. The code supports numbers up-to 4 digits, i.e., numbers from 0 to 9999. Idea is to create arrays that store individual parts of output strings. One array is used for single digits, one for numbers from 10 to 19, one for 20, 30, 40, 50, .. etc, and one for powers of 10. 
The given number is divided in two parts: first two digits and last two digits, and the two parts are printed separately. 

C++

// C++ program for above approach
#include <bits/stdc++.h>
using namespace std;

/* A function that prints given number in words */
void convert_to_words(char* num)
{
  int len = strlen(
    num); // Get number of digits in given number

  /* Base cases */
  if (len == 0) {
    cout << "empty string" << endl;
    return;
  }
  if (len > 4) {
    cout <<"Length more than 4 is not supported\n" << endl;
    return;
  }

  /* The first string is not used, it is to make
        array indexing simple */
  char* single_digits[]
    = { "zero", "one", "two ",   "three ", "four",
       "five ", "six", "seven", "eight ", "nine " };

  /* The first string is not used, it is to make
        array indexing simple */
  char* two_digits[]
    = { "",          "ten",      "eleven",  "twelve",
       "thirteen",  "fourteen", "fifteen", "sixteen",
       "seventeen", "eighteen", "nineteen" };

  /* The first two string are not used, they are to make
        array indexing simple*/
  char* tens_multiple[] = { "",       "",        "twenty ",
                           "thirty", "forty",   "fifty",
                           "sixty",  "seventy", "eighty ",
                           "ninety " };

  char* tens_power[] = { "hundred ", "thousand " };

  /* Used for debugging purpose only */
  cout << endl;
  cout << num << ": ";

  /* For single digit number */
  if (len == 1) {
    cout << single_digits[*num - '0'] << endl;
    return;
  }

  /* Iterate while num is not '\0' */
  while (*num != '\0') {

    /* Code path for first 2 digits */
    if (len >= 3) {
      if (*num - '0' != 0) {
        cout << single_digits[*num - '0'];
        cout << tens_power[len - 3]; // here len can
        // be 3 or 4
      }
      --len;
    }

    /* Code path for last 2 digits */
    else {
      /* Need to explicitly handle 10-19. Sum of the
            two digits is used as index of "two_digits"
            array of strings */
      if (*num == '1') {
        int sum = *num - '0' + *(num + 1) - '0';
        cout << two_digits[sum] << endl;
        return;
      }

      /* Need to explicitly handle 20 */
      else if (*num == '2' && *(num + 1) == '0') {
        cout <<"twenty" << endl;
        return;
      }

      /* Rest of the two digit numbers i.e., 21 to 99
             */
      else {
        int i = *num - '0';
        if (i > 0)
          cout << tens_multiple[i]  << " ";
        else
          cout << "";
        ++num;
        if (*num != '0')
          cout << single_digits[*num - '0'];
      }
    }
    ++num;
  }
}

// Driver Code
int main()
{
  convert_to_words("9923");
  convert_to_words("523");
  convert_to_words("89");
  convert_to_words("8");
}

// This code is contributed by sanjoy_62.

C

/* C program to print a given number in words. The program
handles numbers from 0 to 9999 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* A function that prints given number in words */
void convert_to_words(char* num)
{
    int len = strlen(
        num); // Get number of digits in given number

    /* Base cases */
    if (len == 0) {
        fprintf(stderr, "empty string\n");
        return;
    }
    if (len > 4) {
        fprintf(stderr,
                "Length more than 4 is not supported\n");
        return;
    }

    /* The first string is not used, it is to make
        array indexing simple */
    char* single_digits[]
        = { "zero", "one", "two",   "three", "four",
            "five", "six", "seven", "eight", "nine" };

    /* The first string is not used, it is to make
        array indexing simple */
    char* two_digits[]
        = { "",          "ten",      "eleven",  "twelve",
            "thirteen",  "fourteen", "fifteen", "sixteen",
            "seventeen", "eighteen", "nineteen" };

    /* The first two string are not used, they are to make
        array indexing simple*/
    char* tens_multiple[] = { "",       "",        "twenty",
                              "thirty", "forty",   "fifty",
                              "sixty",  "seventy", "eighty",
                              "ninety" };

    char* tens_power[] = { "hundred", "thousand" };

    /* Used for debugging purpose only */
    printf("\n%s: ", num);

    /* For single digit number */
    if (len == 1) {
        printf("%s\n", single_digits[*num - '0']);
        return;
    }

    /* Iterate while num is not '\0' */
    while (*num != '\0') {

        /* Code path for first 2 digits */
        if (len >= 3) {
            if (*num - '0' != 0) {
                printf("%s ", single_digits[*num - '0']);
                printf("%s ",
                       tens_power[len - 3]); // here len can
                                             // be 3 or 4
            }
            --len;
        }

        /* Code path for last 2 digits */
        else {
            /* Need to explicitly handle 10-19. Sum of the
            two digits is used as index of "two_digits"
            array of strings */
            if (*num == '1') {
                int sum = *num - '0' + *(num + 1) - '0';
                printf("%s\n", two_digits[sum]);
                return;
            }

            /* Need to explicitly handle 20 */
            else if (*num == '2' && *(num + 1) == '0') {
                printf("twenty\n");
                return;
            }

            /* Rest of the two digit numbers i.e., 21 to 99
             */
            else {
                int i = *num - '0';
                printf("%s ", i ? tens_multiple[i] : "");
                ++num;
                if (*num != '0')
                    printf("%s ",
                           single_digits[*num - '0']);
            }
        }
        ++num;
    }
}

/* Driver program to test above function */
int main(void)
{
    convert_to_words("9923");
    convert_to_words("523");
    convert_to_words("89");
    convert_to_words("8");

    return 0;
}

Java

// Java program to print a given number in words. The
// program handles numbers from 0 to 9999

class GFG {
    // A function that prints
    // given number in words
    static void convert_to_words(char[] num)
    {
        // Get number of digits
        // in given number
        int len = num.length;

        // Base cases
        if (len == 0) {
            System.out.println("empty string");
            return;
        }
        if (len > 4) {
            System.out.println(
                "Length more than 4 is not supported");
            return;
        }

        /* The first string is not used, it is to make
            array indexing simple */
        String[] single_digits = new String[] {
            "zero", "one", "two",   "three", "four",
            "five", "six", "seven", "eight", "nine"
        };

        /* The first string is not used, it is to make
            array indexing simple */
        String[] two_digits = new String[] {
            "",          "ten",      "eleven",  "twelve",
            "thirteen",  "fourteen", "fifteen", "sixteen",
            "seventeen", "eighteen", "nineteen"
        };

        /* The first two string are not used, they are to
         * make array indexing simple*/
        String[] tens_multiple = new String[] {
            "",      "",      "twenty",  "thirty", "forty",
            "fifty", "sixty", "seventy", "eighty", "ninety"
        };

        String[] tens_power
            = new String[] { "hundred", "thousand" };

        /* Used for debugging purpose only */
        System.out.print(String.valueOf(num) + ": ");

        /* For single digit number */
        if (len == 1) {
            System.out.println(single_digits[num[0] - '0']);
            return;
        }

        /* Iterate while num
            is not '\0' */
        int x = 0;
        while (x < num.length) {

            /* Code path for first 2 digits */
            if (len >= 3) {
                if (num[x] - '0' != 0) {
                    System.out.print(
                        single_digits[num[x] - '0'] + " ");
                    System.out.print(tens_power[len - 3]
                                     + " ");
                    // here len can be 3 or 4
                }
                --len;
            }

            /* Code path for last 2 digits */
            else {
                /* Need to explicitly handle
                10-19. Sum of the two digits
                is used as index of "two_digits"
                array of strings */
                if (num[x] - '0' == 1) {
                    int sum
                        = num[x] - '0' + num[x + 1] - '0';
                    System.out.println(two_digits[sum]);
                    return;
                }

                /* Need to explicitly handle 20 */
                else if (num[x] - '0' == 2
                         && num[x + 1] - '0' == 0) {
                    System.out.println("twenty");
                    return;
                }

                /* Rest of the two digit
                numbers i.e., 21 to 99 */
                else {
                    int i = (num[x] - '0');
                    if (i > 0)
                        System.out.print(tens_multiple[i]
                                         + " ");
                    else
                        System.out.print("");
                    ++x;
                    if (num[x] - '0' != 0)
                        System.out.println(
                            single_digits[num[x] - '0']);
                }
            }
            ++x;
        }
    }

    // Driver Code
    public static void main(String[] args)
    {
        convert_to_words("9923".toCharArray());
        convert_to_words("523".toCharArray());
        convert_to_words("89".toCharArray());
        convert_to_words("8".toCharArray());
    }
}
// This code is contributed
// by Mithun Kumar

Python3

# Python program to print a given number in
# words. The program handles numbers
# from 0 to 9999

# A function that prints
# given number in words


def convert_to_words(num):

    # Get number of digits
    # in given number
    l = len(num)

    # Base cases
    if (l == 0):
        print("empty string")
        return

    if (l > 4):
        print("Length more than 4 is not supported")
        return

    # The first string is not used,
    # it is to make array indexing simple
    single_digits = ["zero", "one", "two", "three",
                     "four", "five", "six", "seven",
                     "eight", "nine"]

    # The first string is not used,
    # it is to make array indexing simple
    two_digits = ["", "ten", "eleven", "twelve",
                  "thirteen", "fourteen", "fifteen",
                  "sixteen", "seventeen", "eighteen",
                  "nineteen"]

    # The first two string are not used,
    # they are to make array indexing simple
    tens_multiple = ["", "", "twenty", "thirty", "forty",
                     "fifty", "sixty", "seventy", "eighty",
                     "ninety"]

    tens_power = ["hundred", "thousand"]

    # Used for debugging purpose only
    print(num, ":", end=" ")

    # For single digit number
    if (l == 1):
        print(single_digits[ord(num[0]) - 48])
        return

    # Iterate while num is not '\0'
    x = 0
    while (x < len(num)):

        # Code path for first 2 digits
        if (l >= 3):
            if (ord(num[x]) - 48 != 0):
                print(single_digits[ord(num[x]) - 48],
                      end=" ")
                print(tens_power[l - 3], end=" ")
                # here len can be 3 or 4

            l -= 1

        # Code path for last 2 digits
        else:

            # Need to explicitly handle
            # 10-19. Sum of the two digits
            # is used as index of "two_digits"
            # array of strings
            if (ord(num[x]) - 48 == 1):
                sum = (ord(num[x]) - 48 +
                       ord(num[x+1]) - 48)
                print(two_digits[sum])
                return

            # Need to explicitly handle 20
            elif (ord(num[x]) - 48 == 2 and
                  ord(num[x + 1]) - 48 == 0):
                print("twenty")
                return

            # Rest of the two digit
            # numbers i.e., 21 to 99
            else:
                i = ord(num[x]) - 48
                if(i > 0):
                    print(tens_multiple[i], end=" ")
                else:
                    print("", end="")
                x += 1
                if(ord(num[x]) - 48 != 0):
                    print(single_digits[ord(num[x]) - 48])
        x += 1


# Driver Code
convert_to_words("9923") # Four Digits
convert_to_words("523") # Three Digits
convert_to_words("89") # Two Digits
convert_to_words("8") # One Digits

# This code is contributed
# by Mithun Kumar

C#

// C# program to print a given
// number in words. The program
// handles numbers from 0 to 9999
using System;

class GFG {
    // A function that prints
    // given number in words
    static void convert_to_words(char[] num)
    {
        // Get number of digits
        // in given number
        int len = num.Length;

        // Base cases
        if (len == 0) {
            Console.WriteLine("empty string");
            return;
        }
        if (len > 4) {
            Console.WriteLine("Length more than "
                              + "4 is not supported");
            return;
        }

        /* The first string is not used,
           it is to make array indexing simple */
        string[] single_digits = new string[] {
            "zero", "one", "two",   "three", "four",
            "five", "six", "seven", "eight", "nine"
        };

        /* The first string is not used,
           it is to make array indexing simple */
        string[] two_digits = new string[] {
            "",          "ten",      "eleven",  "twelve",
            "thirteen",  "fourteen", "fifteen", "sixteen",
            "seventeen", "eighteen", "nineteen"
        };

        /* The first two string are not used,
           they are to make array indexing simple*/
        string[] tens_multiple = new string[] {
            "",      "",      "twenty",  "thirty", "forty",
            "fifty", "sixty", "seventy", "eighty", "ninety"
        };

        string[] tens_power
            = new string[] { "hundred", "thousand" };

        /* Used for debugging purpose only */
        Console.Write((new string(num)) + ": ");

        /* For single digit number */
        if (len == 1) {
            Console.WriteLine(single_digits[num[0] - '0']);
            return;
        }

        /* Iterate while num
            is not '\0' */
        int x = 0;
        while (x < num.Length) {

            /* Code path for first 2 digits */
            if (len >= 3) {
                if (num[x] - '0' != 0) {
                    Console.Write(
                        single_digits[num[x] - '0'] + " ");
                    Console.Write(tens_power[len - 3]
                                  + " ");

                    // here len can be 3 or 4
                }
                --len;
            }

            /* Code path for last 2 digits */
            else {
                /* Need to explicitly handle
                10-19. Sum of the two digits
                is used as index of "two_digits"
                array of strings */
                if (num[x] - '0' == 1) {
                    int sum = num[x] - '0' + num[x + 1] - '0';
                    Console.WriteLine(two_digits[sum]);
                    return;
                }

                /* Need to explicitly handle 20 */
                else if (num[x] - '0' == 2
                         && num[x + 1] - '0' == 0) {
                    Console.WriteLine("twenty");
                    return;
                }

                /* Rest of the two digit
                numbers i.e., 21 to 99 */
                else {
                    int i = (num[x] - '0');
                    if (i > 0)
                        Console.Write(tens_multiple[i]
                                      + " ");
                    else
                        Console.Write("");
                    ++x;
                    if (num[x] - '0' != 0)
                        Console.WriteLine(
                            single_digits[num[x] - '0']);
                }
            }
            ++x;
        }
    }

    // Driver Code
    public static void Main()
    {
        convert_to_words("9923".ToCharArray());
        convert_to_words("523".ToCharArray());
        convert_to_words("89".ToCharArray());
        convert_to_words("8".ToCharArray());
    }
}

// This code is contributed
// by Mits

PHP

<?php
// PHP program to print a given
// number in words. The
// program handles numbers
// from 0 to 9999

// A function that prints
// given number in words
function convert_to_words($num)
{
    // Get number of digits
    // in given number
    $len = strlen($num);

    // Base cases
    if ($len == 0)
    {
        echo "empty string\n";
        return;
    }
    if ($len > 4)
    {
        echo "Length more than 4 " .
               "is not supported\n";
        return;
    }

    /* The first string is not used,
    it is to make array indexing simple */
    $single_digits = array("zero", "one", "two",
                           "three", "four", "five",
                           "six", "seven", "eight",
                                           "nine");

    /* The first string is not used,
    it is to make array indexing simple */
    $two_digits = array("", "ten", "eleven", "twelve",
                        "thirteen", "fourteen", "fifteen",
                        "sixteen", "seventeen", "eighteen",
                                               "nineteen");

    /* The first two string are not used,
    they are to make array indexing simple*/
    $tens_multiple = array("", "", "twenty", "thirty",
                           "forty", "fifty", "sixty",
                           "seventy", "eighty", "ninety");

    $tens_power = array("hundred", "thousand");

    /* Used for debugging purpose only */
    echo $num.": ";

    /* For single digit number */
    if ($len == 1)
    {
        echo $single_digits[$num[0] - '0'] . " \n";
        return;
    }

    /* Iterate while num
        is not '\0' */
    $x = 0;
    while ($x < strlen($num))
    {

        /* Code path for first 2 digits */
        if ($len >= 3)
        {
            if ($num[$x]-'0' != 0)
            {
                echo $single_digits[$num[$x] - '0'] . " ";
                echo $tens_power[$len - 3] . " ";
                // here len can be 3 or 4
            }
            --$len;
        }

        /* Code path for last 2 digits */
        else
        {
            /* Need to explicitly handle
            10-19. Sum of the two digits
            is used as index of "two_digits"
            array of strings */
            if ($num[$x] - '0' == 1)
            {
                $sum = $num[$x] - '0' +
                       $num[$x] - '0';
                echo $two_digits[$sum] . " \n";
                return;
            }

            /* Need to explicitly handle 20 */
            else if ($num[$x] - '0' == 2 &&
                     $num[$x + 1] - '0' == 0)
            {
                echo "twenty\n";
                return;
            }

            /* Rest of the two digit
            numbers i.e., 21 to 99 */
            else
            {
                $i = $num[$x] - '0';
                if($i > 0)
                echo $tens_multiple[$i] . " ";
                else
                echo "";
                ++$x;
                if ($num[$x] - '0' != 0)
                    echo $single_digits[$num[$x] -
                                     '0'] . " \n";
            }
        }
        ++$x;
    }
}

// Driver Code
convert_to_words("9923");
convert_to_words("523");
convert_to_words("89");
convert_to_words("8");

// This code is contributed
// by Mithun Kumar
?>

Javascript

<script>

// JavaScript program to document.write a given number in
// words. The program handles numbers
// from 0 to 9999

// A function that document.writes
// given number in words
function convert_to_words(num){

    // Get number of digits
    // in given number
    let l = num.length

    // Base cases
    if (l == 0){
        document.write("empty string","</br>")
        return
    }

    if (l > 4){
        document.write("Length more than 4 is not supported","</br>")
        return
    }

    // The first string is not used,
    // it is to make array indexing simple
    let single_digits = ["zero", "one", "two", "three",
                     "four", "five", "six", "seven",
                     "eight", "nine"]

    // The first string is not used,
    // it is to make array indexing simple
    let two_digits = ["", "ten", "eleven", "twelve",
                  "thirteen", "fourteen", "fifteen",
                  "sixteen", "seventeen", "eighteen",
                  "nineteen"]

    // The first two string are not used,
    // they are to make array indexing simple
    let tens_multiple = ["", "", "twenty", "thirty", "forty",
                     "fifty", "sixty", "seventy", "eighty",
                     "ninety"]

    let tens_power = ["hundred", "thousand"]

    // Used for debugging purpose only
    document.write(num, ":"," ")

    // For single digit number
    if (l == 1){
        document.write(single_digits[num.charCodeAt(0) - 48],"</br>")
        return
    }

    // Iterate while num is not '\0'
    let x = 0
    while (x < num.length){

        // Code path for first 2 digits
        if (l >= 3){
            if (num.charCodeAt(x) - 48 != 0){
                document.write(single_digits[num.charCodeAt(x) - 48]," ")
                document.write(tens_power[l - 3]," ")
                // here len can be 3 or 4
            }

            l -= 1
        }

        // Code path for last 2 digits
        else{

            // Need to explicitly handle
            // 10-19. Sum of the two digits
            // is used as index of "two_digits"
            // array of strings
            if (num.charCodeAt(x) - 48 == 1){
                sum = (num.charCodeAt(x) - 48 + num.charCodeAt(x+1) - 48)
                document.write(two_digits[sum],"</br>")
                return
            }

            // Need to explicitly handle 20
            else if (num.charCodeAt(x) - 48 == 2 &&
                  num.charCodeAt(x + 1) - 48 == 0){
                document.write("twenty","</br>")
                return
            }

            // Rest of the two digit
            // numbers i.e., 21 to 99
            else{
                i = num.charCodeAt(x) - 48
                if(i > 0)
                    document.write(tens_multiple[i], end=" ")
                else
                    document.write("", end="")
                x += 1
                if(num.charCodeAt(x) - 48 != 0)
                    document.write(single_digits[num.charCodeAt(x) - 48],"</br>")
            }
        }
        x += 1
    }

}

// Driver Code
convert_to_words("9923") // Four Digits
convert_to_words("523") // Three Digits
convert_to_words("89") // Two Digits
convert_to_words("8") // One Digits

// This code is contributed by shinjanpatra

</script>

Output:

9923: nine thousand nine hundred twenty three
523: five hundred twenty three
89: eighty nine
8989: eight thousand nine hundred eighty nine

This article is compiled by Narendra Kangralkar. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.