C Program to find product of digits of a number

Understanding the Problem

• Goal: Write a C program that calculates the product of the individual digits of a given integer.
• Key Concepts:
  • Modulo operator (%): Extracting individual digits.
  • Loops: while loop for repeated operations.
  • Mathematical calculations: Multiplying digits using the * operator.

Step-by-Step Guide

1. Header Inclusion

C

#include <stdio.h>

• Explanation: Includes the standard input/output library for functions like printf and scanf.

2. Main Function

C

int main() {
    // Code statements here
    return 0;
}

3. Get Input Number

C

int num, product = 1;
printf("Enter a number: ");
scanf("%d", &num);

• Explanation:
  • Declares num to store the input number and product to store the calculated product (initialized to 1).
  • Prompts the user to enter a number and reads it using scanf.

4. Loop to Extract and Multiply Digits

C

while (num > 0) {
    int digit = num % 10;  // Extract the last digit
    product *= digit;     // Multiply the digit to the product
    num /= 10;            // Remove the last digit from the number
}

• Explanation:
  • num % 10: Extracts the last digit using the modulo operator.
  • product *= digit: Multiplies the extracted digit to the product variable.
  • num /= 10: Removes the last digit from num by dividing it by 10.

5. Print the Product

C

printf("Product of digits: %d\n", product);

6. Complete Code

C

#include <stdio.h>

int main() {
    int num, product = 1;

    printf("Enter a number: ");
    scanf("%d", &num);

    while (num > 0) {
        int digit = num % 10;
        product *= digit;
        num /= 10;
    }

    printf("Product of digits: %d\n", product);

    return 0;
}

7. Executing the Program

1. Save the code as a .c file (e.g., product_of_digits.c).
2. Compile using a C compiler (e.g., gcc product_of_digits.c -o product_of_digits).
3. Run the executable (e.g., ./product_of_digits).

Example Output

Enter a number: 12345 Product of digits: 120