Program to Convert Digit/Number to Words in C

Converting Numbers to Words

Converting a number to words is a common problem in programming.

We will explore three different methods to achieve this in C.

Method 1: Using Arrays

This method utilizes arrays to map digits to their word equivalents.

#include <stdio.h>

void convertToWords(int num) {
    char *single_digits[] = {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};
    printf("%s", single_digits[num]);
}

int main() {
    int num;
    printf("Enter a single-digit number: ");
    scanf("%d", &num);
    if (num >= 0 && num <= 9)
        convertToWords(num);
    else
        printf("Invalid input!");
    return 0;
}
            

Method 2: Using String Manipulation

This method handles multi-digit numbers using a loop.

#include <stdio.h>
#include <string.h>

void convertToWords(int num) {
    char *single_digits[] = {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};
    char str[20];
    sprintf(str, "%d", num);
    for (int i = 0; i < strlen(str); i++) {
        printf("%s ", single_digits[str[i] - '0']);
    }
}

int main() {
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    convertToWords(num);
    return 0;
}
            

Method 3: Using Recursion

This method recursively processes each digit.

#include <stdio.h>

char *single_digits[] = {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};

void convertToWordsRecursive(int num) {
    if (num == 0)
        return;
    convertToWordsRecursive(num / 10);
    printf("%s ", single_digits[num % 10]);
}

int main() {
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    if (num == 0)
        printf("Zero");
    else
        convertToWordsRecursive(num);
    return 0;
}