C program to print number in words

In this blog post, we learn how to write a C program to print number in words?. We will write the C program to print numbers in words using switch cases. How to display number in words using loop in C programming. Write a C program to input a number from user and print it into words using for loop. Logic to print number in words in C programming.

Example,

Input:
Input number: 2726


Output:
Two Seven Two Six

Logic to print number in words:

1. Ask the user to enter a positive integer number like 2724 and store it in an integer variable.
2. Reverse the entered number, if you don’t know how to reverse a number, you can see the article “How to reverse a number”.
3. Extract the last digit of a given number by performing modulo division by 10 and store the result in a variable.
4. Now create a switch case to print digit 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
5. Remove the last digit of a number
6. Repeat steps 3 to 5 until the number becomes 0.

C program to print number in words:

#include <stdio.h>
#include <math.h>

int main()
{
    int data, num = 0, digits;

    //Ask the user to enter the number
    printf("Enter any number to print in words: ");
    scanf("%d", &data);

    //Get all digits of entered number
    digits = (int) log10(data);

    //Store reverse of data in num
    while(data != 0)
    {
        num = (num * 10) + (data % 10);
        data /= 10;
    }

    // Find total number of trailing zeros
    digits =  digits - ((int) log10(num));

    //Extract last digit of number and print corresponding number in words
    //till num becomes 0
    while(num != 0)
    {
        switch(num % 10)
        {
        case 0:
            printf("Zero ");
            break;
        case 1:
            printf("One ");
            break;
        case 2:
            printf("Two ");
            break;
        case 3:
            printf("Three ");
            break;
        case 4:
            printf("Four ");
            break;
        case 5:
            printf("Five ");
            break;
        case 6:
            printf("Six ");
            break;
        case 7:
            printf("Seven ");
            break;
        case 8:
            printf("Eight ");
            break;
        case 9:
            printf("Nine ");
            break;
        }

        num /= 10;
    }

    // Print all trailing 0
    while(digits)
    {
        printf("Zero ");
        digits--;
    }

    return 0;
}

Output:

Enter any number to print in words: 2726
Two Seven Two Six