Introduction

In programming, one common task is converting numerical values into their word form. This is a useful skill in applications like checks, invoices, and formal documentation. In this tutorial, we will demonstrate how to convert a number into its word representation using C++.

Objective

The objective of this program is to provide a simple and effective solution to convert any given number into its corresponding word form. Whether it’s a small number like 1 or a large number like 12345, this program will handle them all and output their word equivalents.

C++ Code

#include 
#include 
#include 
using namespace std;

vector ones = { "", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" };
vector teens = { "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
vector tens = { "", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };
vector thousands = { "", "Thousand", "Million", "Billion", "Trillion" };

string convertToWords(int num) {
    if (num == 0) return "Zero";
    string result = "";
    int idx = 0;

    while (num > 0) {
        if (num % 1000 != 0) {
            result = convertLessThanThousand(num % 1000) + thousands[idx] + " " + result;
        }
        num /= 1000;
        idx++;
    }
    return result;
}

string convertLessThanThousand(int num) {
    string result = "";
    if (num >= 100) {
        result += ones[num / 100] + " Hundred ";
        num %= 100;
    }
    if (num >= 20) {
        result += tens[num / 10] + " ";
        num %= 10;
    }
    if (num >= 10) {
        result += teens[num - 10] + " ";
    } else if (num > 0) {
        result += ones[num] + " ";
    }
    return result;
}

int main() {
    int num;
    cout << "Enter a number: "; cin >> num;
    cout << "Number in words: " << convertToWords(num) << endl;
    return 0;
}

Explanation of the Program

The program is structured in the following way:

• Vectors: The program defines four vectors to store words for single digits, teens, tens, and place values (thousand, million, etc.).
• convertToWords function: This is the main function that handles the conversion of a number into words. It processes the number in chunks of three digits (thousands, millions, etc.).
• convertLessThanThousand function: This function converts numbers less than 1000 into words. It first processes the hundreds, then tens, and finally ones.
• main function: It prompts the user to enter a number, calls the conversion function, and prints the resulting word form.

How to Run the Program

Follow these steps to run the program:

1. Write the code in a text editor and save it with a “.cpp” extension.
2. Compile the program using a C++ compiler like g++. For example, run the command: g++ -o number_to_words number_to_words.cpp
3. Run the program: ./number_to_words
4. Enter a number when prompted, and the program will display the number in words.