Write code to convert given number into words (eg

Question

Write C/C++/Java code to convert given number into words.

eg:- Input: 1234

Output: One thousand two hundred thirty-four.

Input: 10

Output: Ten

Does it require a complete switch case for digits 0 to 10.

Adding "teen" after every number name (eg: 14: four "teen".) from 14 to 19.

And than adding "ty" and the digits name for a number in the range 20 to 99.

And so on.

I think there must be some far better approach for solving this.

C code is preferred.

Answer 1

#include<stdio.h>
#include<conio.h>
void main()
{
int len=0,revnum,i,dup=0,j=0,k=0;

 long int gvalue;

 char  ones[]  [10]={"one","Two","Three","Four","Five","Six","Seven","Eight","Nine","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen",""};

 char twos[][10]={"Ten","Twenty","Thirty","Fourty","fifty","Sixty","Seventy","eighty","Ninety",""};

clrscr();


 printf("\n Enter value"); 

 scanf("%ld",&gvalue);
 if(gvalue==10)

   printf("Ten");

 else if(gvalue==100)

   printf("Hundred");

 else if(gvalue==1000)

   printf("Thousand");

 dup=gvalue;

 for(i=0;dup>0;i++)
  {
   revnum=revnum*10+dup%10;

   len++;

   dup=dup/10;

  }

 while(j<len)

 {

 if(gvalue<10)

  {

   printf("%s ",ones[gvalue-1]);

   }

 else if(gvalue>10&&gvalue<=19)

  {

   printf("%s ",ones[gvalue-2]);

   break;

  }

 else if(gvalue>19&&gvalue<100)

  {

   k=gvalue/10;

   gvalue=gvalue%10;

    printf("%s ",twos[k-1]);

   }

  else if(gvalue>100&&gvalue<1000)

   {

    k=gvalue/100;

    gvalue=gvalue%100;

    printf("%s Hundred ",ones[k-1]);

     }

   else if(gvalue>=1000&&gvlaue<9999)

   {

    k=gvalue/1000;

    gvalue=gvalue%1000;

    printf("%s Thousand ",ones[k-1]);

    }

   else if(gvalue>=11000&&gvalue<=19000)

    {

    k=gvalue/1000;

    gvalue=gvalue%1000;

    printf("%s Thousand ",twos[k-2]);

    }

   else if(gvalue>=12000&&gvalue<100000)

   {

    k=gvalue/10000;

    gvalue=gvalue%10000;

    printf("%s ",ones[gvalue-1]);

   }

else

{

printf("");

}

 j++;

 getch();

}

Answer 2

/* This Program will convert Numbers from -999,999,999 to 999,999,999 into words */

#include <vector>
#include <iostream>
#include <stdexcept>
#include <string>

using namespace std;

const std::vector<std::string> first14 = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen" };
const std::vector<std::string> prefixes = { "twen", "thir", "for", "fif", "six", "seven", "eigh", "nine" };

std::string inttostr(const int number)
{
    if (number < 0)
    {
        return "minus " + inttostr(-number);
    }
    if (number <= 14)
        return first14.at(number);
    if (number < 20)
        return prefixes.at(number - 12) + "teen";
    if (number < 100) {
        unsigned int remainder = number - (static_cast<int>(number / 10) * 10);
        return prefixes.at(number / 10 - 2) + (0 != remainder ? "ty " + inttostr(remainder) : "ty");
    }
    if (number < 1000) {
        unsigned int remainder = number - (static_cast<int>(number / 100) * 100);
        return first14.at(number / 100) + (0 != remainder ? " hundred " + inttostr(remainder) : " hundred");
    }
    if (number < 1000000) {
        unsigned int thousands = static_cast<int>(number / 1000);
        unsigned int remainder = number - (thousands * 1000);
        return inttostr(thousands) + (0 != remainder ? " thousand " + inttostr(remainder) : " thousand");
    }
    if (number < 1000000000) {
        unsigned int millions = static_cast<int>(number / 1000000);
        unsigned int remainder = number - (millions * 1000000);
        return inttostr(millions) + (0 != remainder ? " million " + inttostr(remainder) : " million");
    }
    throw std::out_of_range("inttostr() value too large");
}

int main()
{
    int num;
    cout << "Enter a number to convert it into letters : ";
    cin >> num;
    cout << endl << num << " = " << inttostr(num) << endl;
    system("pause");
    return 0;
}

Answer 3

#include<iostream>
using namespace std;
void expand(int);
int main()
{
    int num;
    cout<<"Enter a number : ";
    cin>>num;
    expand(num);
}
void expand(int value)
{
    const char * const ones[20] = {"zero", "one", "two", "three","four","five","six","seven",
    "eight","nine","ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen",
    "eighteen","nineteen"};
    const char * const tens[10] = {"", "ten", "twenty", "thirty","forty","fifty","sixty","seventy",
    "eighty","ninety"};

    if(value<0)
    {
        cout<<"minus ";
        expand(-value);
    }
    else if(value>=1000)
    {
        expand(value/1000);
        cout<<" thousand";
        if(value % 1000)
        {
            if(value % 1000 < 100)
            {
                cout << " and";
            }
            cout << " " ;
            expand(value % 1000);
        }
    }
    else if(value >= 100)
    {
        expand(value / 100);
        cout<<" hundred";
        if(value % 100)
        {
            cout << " and ";
            expand (value % 100);
        }
    }
    else if(value >= 20)
    {
        cout << tens[value / 10];
        if(value % 10)
        {
            cout << " ";
            expand(value % 10);
        }
    }
    else
    {
        cout<<ones[value];
    }
    return;
}

Answer 4

Instead of switch statements, consider using tables of strings indexed by a small value.

const char * const ones[20] = {"zero", "one", "two", ..., "nineteen"};
const char * const tens[10] = {"", "ten", "twenty", ..., "ninety"};

Now break the problem into small pieces. Write a function that can output a single-digit number. Then write a function that can handle a two-digit number (which will probably use the previous function). Continue building up the functions as necessary.

Create a list of test cases with expected output, and write code to call your functions and check the output, so that, as you fix problems for the more complicated cases, you can be sure that the simpler cases continue to work.

Answer 5

/*Maximum value that can be entered is 2,147,483,647
 * Program to convert entered number into string
 * */
import java.util.Scanner;

public class NumberToWords 
{

public static void main(String[] args) 
{
    double num;//for taking input number
    Scanner obj=new Scanner(System.in);
    do
    {
        System.out.println("\n\nEnter the Number (Maximum value that can be entered is 2,147,483,647)");
        num=obj.nextDouble();
        if(num<=2147483647)//checking if entered number exceeds maximum integer value
        {
            int number=(int)num;//type casting double number to integer number
            splitNumber(number);//calling splitNumber-it will split complete number in pairs of 3 digits
        }
        else
            System.out.println("Enter smaller value");//asking user to enter a smaller value compared to 2,147,483,647
    }while(num>2147483647);
}
//function to split complete number into pair of 3 digits each
public static void splitNumber(int number)
{   //splitNumber array-contains the numbers in pair of 3 digits
    int splitNumber[]=new int[4],temp=number,i=0,index;
    //splitting number into pair of 3
    if(temp==0)
        System.out.println("zero");
    while(temp!=0)
    {
        splitNumber[i++]=temp%1000;
        temp/=1000;
    }
    //passing each pair of 3 digits to another function
    for(int j=i-1;j>-1;j--)
    {   //toWords function will split pair of 3 digits to separate digits
        if(splitNumber[j]!=0)
            {toWords(splitNumber[j]);
        if(j==3)//if the number contained more than 9 digits
            System.out.print("billion,");
        else if(j==2)//if the number contained more than 6 digits & less than 10 digits
            System.out.print("million,");
        else if(j==1)
            System.out.print("thousand,");//if the number contained more than 3 digits & less than 7 digits
            }
            }       
}
//function that splits number into individual digits
public static void toWords(int number)
    //splitSmallNumber array contains individual digits of number passed to this function
{   int splitSmallNumber[]=new int[3],i=0,j;
    int temp=number;//making temporary copy of the number
    //logic to split number into its constituent digits

    while(temp!=0)
    {
        splitSmallNumber[i++]=temp%10;
        temp/=10;
    }
    //printing words for each digit
    for(j=i-1;j>-1;j--)
      //{   if the digit is greater than zero
        if(splitSmallNumber[j]>=0)
            //if the digit is at 3rd place or if digit is at (1st place with digit at 2nd place not equal to zero)
        {   if(j==2||(j==0 && (splitSmallNumber[1]!=1)))
            {
                switch(splitSmallNumber[j])
                {

                    case 1:System.out.print("one ");break;
                    case 2:System.out.print("two ");break;
                    case 3:System.out.print("three ");break;
                    case 4:System.out.print("four ");break;
                    case 5:System.out.print("five ");break;
                    case 6:System.out.print("six ");break;
                    case 7:System.out.print("seven ");break;
                    case 8:System.out.print("eight ");break;
                    case 9:System.out.print("nine ");break;

            }

        }
        //if digit is at 2nd place
        if(j==1)
        {       //if digit at 2nd place is 0 or 1
                if(((splitSmallNumber[j]==0)||(splitSmallNumber[j]==1))&& splitSmallNumber[2]!=0 )
                System.out.print("hundred ");
            switch(splitSmallNumber[1])
            {   case 1://if digit at 2nd place is 1 example-213
                        switch(splitSmallNumber[0])
                        {
                        case 1:System.out.print("eleven ");break;
                        case 2:System.out.print("twelve ");break;
                        case 3:System.out.print("thirteen ");break;
                        case 4:System.out.print("fourteen ");break;
                        case 5:System.out.print("fifteen ");break;
                        case 6:System.out.print("sixteen ");break;
                        case 7:System.out.print("seventeen ");break;
                        case 8:System.out.print("eighteen ");break;
                        case 9:System.out.print("nineteen ");break;
                        case 0:System.out.print("ten ");break;
                        }break;
                        //if digit at 2nd place is not 1
                    case 2:System.out.print("twenty ");break;
                    case 3:System.out.print("thirty ");break;
                    case 4:System.out.print("forty ");break;
                    case 5:System.out.print("fifty ");break;
                    case 6:System.out.print("sixty ");break;
                    case 7:System.out.print("seventy ");break;
                    case 8:System.out.print("eighty ");break;
                    case 9:System.out.print("ninety ");break;
                    //case 0:   System.out.println("hundred ");break;

            }                           
        }           
    }
  }

}

Answer 6

if you are interested in a ready solution then you may look at HumanizerCpp library (https://github.com/trodevel/HumanizerCpp) - it is a port of C# Humanizer library and it does exactly what you want.

It can even convert to ordinals and currently supports 3 languages: English, German and Russian.

Example:

const INumberToWordsConverter * e = Configurator::GetNumberToWordsConverter( "en" );

std::cout << e->Convert( 123 ) << std::endl;
std::cout << e->Convert( 1234 ) << std::endl;
std::cout << e->Convert( 12345 ) << std::endl;
std::cout << e->Convert( 123456 ) << std::endl;

std::cout << std::endl;
std::cout << e->ConvertToOrdinal( 1001 ) << std::endl;
std::cout << e->ConvertToOrdinal( 1021 ) << std::endl;


const INumberToWordsConverter * g = Configurator::GetNumberToWordsConverter( "de" );

std::cout << std::endl;
std::cout << g->Convert( 123456 ) << std::endl;

const INumberToWordsConverter * r = Configurator::GetNumberToWordsConverter( "ru" );

std::cout << r->ConvertToOrdinal( 1112 ) << std::endl;

Output:

one hundred and twenty-three
one thousand two hundred and thirty-four
twelve thousand three hundred and forty-five
one hundred and twenty-three thousand four hundred and fifty-six

thousand and first
thousand and twenty-first

einhundertdreiundzwanzigtausendvierhundertsechsundfünfzig
одна тысяча сто двенадцатый

In any case you may take a look at the source code and reuse in your project or try to understand the logic. It is written in pure C++ without external libraries.

Regards, Serge