Write code to convert given number into words (eg 1234 as input should output one thousand two hundred and thirty four)

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.

Solution 1

#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;
}

Solution 2

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.

Solution 3

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

Solution 4

/* 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;
}

Solution 5

Works for any number from 0 to 999999999.

This program gets a number from the user, divides it into three parts and stores them separately in an array. The three numbers are passed through a function that convert them into words. Then it adds "million" to the first part and "thousand" to the second part.

#include <iostream>
using namespace std;
int buffer = 0, partFunc[3] = {0, 0, 0}, part[3] = {0, 0, 0}, a, b, c, d;
long input, nFake = 0;
const char ones[][20] = {"",       "one",       "two",      "three",
                         "four",    "five",      "six",      "seven",
                         "eight",   "nine",      "ten",      "eleven",
                         "twelve",  "thirteen",  "fourteen", "fifteen",
                         "sixteen", "seventeen", "eighteen", "nineteen"};
const char tens[][20] = {"",     "ten",   "twenty",  "thirty", "forty",
                         "fifty", "sixty", "seventy", "eighty", "ninety"};
void convert(int funcVar);
int main() {
  cout << "Enter the number:";
  cin >> input;
  nFake = input;
  buffer = 0;
  while (nFake) {
    part[buffer] = nFake % 1000;
    nFake /= 1000;
    buffer++;
  }
  if (buffer == 0) {
    cout << "Zero.";
  } else if (buffer == 1) {
    convert(part[0]);
  } else if (buffer == 2) {
    convert(part[1]);
    cout << " thousand,";
    convert(part[0]);
  } else {
    convert(part[2]);
    cout << " million,";

    if (part[1]) {
      convert(part[1]);
      cout << " thousand,";
    } else {
      cout << "";
    }
    convert(part[0]);
  }
  system("pause");
  return (0);
}

void convert(int funcVar) {
  buffer = 0;
  if (funcVar >= 100) {
    a = funcVar / 100;
    b = funcVar % 100;
    if (b)
      cout << " " << ones[a] << " hundred and";
    else
      cout << " " << ones[a] << " hundred ";
    if (b < 20)
      cout << " " << ones[b];
    else {
      c = b / 10;
      cout << " " << tens[c];
      d = b % 10;
      cout << " " << ones[d];
    }
  } else {
    b = funcVar;
    if (b < 20)
      cout << ones[b];
    else {
      c = b / 10;
      cout << tens[c];
      d = b % 10;
      cout << " " << ones[d];
    }
  }
}

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Comments

[chux - Reinstate Monica]

char ones[] [10]: maybe 20 instead of 10?

[whoan]

Hi IGI30, welcome to Stack Overflow. Code only question are discouraged. Please provide further information.

[davidhigh]

@rgaut: the author forgot to include "ten" into his ones[] array. I corrected it and it seems to work now.

[Jonathan Mee]

@kowsalyajaganathan Wrong language bro.