C++ Program to Check Disarium Number

Posted in C++ Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 20 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, exploring mathematical patterns is a fascinating endeavor. One such numeric pattern is the Disarium number.

A Disarium number is a number defined by the sum of its digits each raised to the power of its respective position.

In this tutorial, we'll delve into a C++ program designed to check whether a given number is a Disarium number.

📄 Example

Let's explore the C++ code that checks whether a given number is a Disarium number.

isDisarium.cpp

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#include <iostream>
#include <cmath>

// Function to count the number of digits in a given number
int countDigits(int number) {
  int count = 0;
  while (number != 0) {
    count++;
    number /= 10;
  }
  return count;
}

// Function to check if a number is a Disarium number
bool isDisarium(int number) {
  int originalNumber = number;
  int digitCount = countDigits(number);
  int sum = 0;

  while (number != 0) {
    int digit = number % 10;
    sum += pow(digit, digitCount);
    digitCount--;
    number /= 10;
  }

  return (sum == originalNumber);
}

// Driver program
int main() {
  // Replace this value with your desired number
  int inputNumber = 89;

  // Call the function to check if the number is Disarium
  if (isDisarium(inputNumber)) {
    std::cout << inputNumber << " is a Disarium number." << std::endl;
  } else {
    std::cout << inputNumber << " is not a Disarium number." << std::endl;
  }

  return 0;
}

💻 Testing the Program

To test the program with different numbers, replace the value of inputNumber in the main function.

Output

89 is a Disarium number.

Compile and run the program to check if the number is a Disarium number.

🧠 How the Program Works

The program defines a function countDigits to count the number of digits in a given number.
The isDisarium function checks if a number is a Disarium number by summing the digits each raised to the power of its position.
The main function tests the isDisarium function with a sample number (replace it with your desired number).

📏 Between the Given Range

Let's take a look at the C++ code that checks for Disarium numbers in the range from 1 to 100.

isDisarium.cpp

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#include <iostream>
#include <cmath>

// Function to check if a number is Disarium
bool isDisarium(int number) {
    int num = number;
    int digitCount = 0;
    int sum = 0;

    // Count digits
    while (num != 0) {
        num /= 10;
        digitCount++;
    }

    // Reset num to original value
    num = number;

    // Calculate sum of digits raised to the power of their position
    while (num != 0) {
        int digit = num % 10;
        sum += pow(digit, digitCount);
        num /= 10;
        digitCount--;
    }

    return sum == number;
}

// Driver program
int main() {
    std::cout << "Disarium numbers in the range 1 to 100:" << std::endl;

    // Check and print Disarium numbers in the range 1 to 100
    for (int i = 1; i <= 100; ++i) {
        if (isDisarium(i)) {
            std::cout << i << " ";
        }
    }

    std::cout << std::endl;

    return 0;
}

💻 Testing the Program

Output

Disarium numbers in the range 1 to 100:
1 2 3 4 5 6 7 8 9 89

Compile and run the program to see the Disarium numbers in the specified range.

🧠 How the Program Works

The program defines a function isDisarium that checks if a given number is a Disarium number.
Inside the function, it calculates the count of digits and then calculates the sum of digits raised to the power of their respective positions.
The main function uses a loop to iterate through numbers from 1 to 100 and prints those that are Disarium numbers.