C++ Program To Determine Divisible Even And Odd Of 2 And 3

This article provides a clear guide on how to write a C++ program that determines if a given number is even, odd, and divisible by 2 or 3. You will learn to apply basic arithmetic operations and conditional logic to categorize numbers effectively.

Problem Statement

Accurately classifying numbers based on their divisibility and parity (even or odd) is a fundamental task in programming. This capability is essential for data validation, filtering, and various mathematical computations. The challenge is to create a robust C++ program that takes an integer input and reports whether it is even, odd, divisible by 2, and divisible by 3.

Example

Consider the number 6. Input: 6 Output: The number 6 is Even. The number 6 is divisible by 2. The number 6 is divisible by 3.

Consider the number 5. Input: 5 Output: The number 5 is Odd. The number 5 is not divisible by 2. The number 5 is not divisible by 3.

Background & Knowledge Prerequisites

To understand this program, readers should be familiar with:

• C++ Basic Syntax: How to write and structure a simple C++ program.
• Variables: Declaring and using integer variables (int).
• Input/Output Operations: Using cout for output and cin for input.
• Conditional Statements: Using if and else for decision-making.
• Modulo Operator (%): Understanding how to use it to find the remainder of a division. For example, number % 2 == 0 checks if a number is even.

Use Cases or Case Studies

Understanding number properties like divisibility and parity has numerous practical applications:

• Data Validation: Ensuring user input meets specific criteria, such as requiring an even number for a certain field.
• Algorithm Optimization: In algorithms, certain operations might only apply to even or odd numbers, or numbers divisible by a specific factor.
• Number Games and Puzzles: Developing games that involve guessing or categorizing numbers based on their properties.
• Resource Allocation: Distributing items evenly or in groups of three.
• Financial Calculations: Identifying transactions that are multiples of certain denominations.

Solution Approaches

This section details a common and straightforward approach to determine the divisibility and parity of a number using C++.

Approach 1: Using the Modulo Operator and Conditional Statements

This approach directly applies the modulo operator (%) within if-else statements to check for even/odd and divisibility by 3.

One-line Summary Read an integer, then use the modulo operator to check its remainder when divided by 2 and 3, printing the corresponding properties.

Code Example

// Divisibility and Parity Checker
#include <iostream>
using namespace std;

int main() {
    int number;

    // Step 1: Prompt the user to enter a number
    cout << "Enter an integer: ";
    cin >> number;

    // Step 2: Determine if the number is Even or Odd
    if (number % 2 == 0) {
        cout << "The number " << number << " is Even." << endl;
    } else {
        cout << "The number " << number << " is Odd." << endl;
    }

    // Step 3: Determine if the number is divisible by 2
    // (This is inherently checked by the Even/Odd logic, but explicitly stated for clarity)
    if (number % 2 == 0) {
        cout << "The number " << number << " is divisible by 2." << endl;
    } else {
        cout << "The number " << number << " is not divisible by 2." << endl;
    }

    // Step 4: Determine if the number is divisible by 3
    if (number % 3 == 0) {
        cout << "The number " << number << " is divisible by 3." << endl;
    } else {
        cout << "The number " << number << " is not divisible by 3." << endl;
    }

    return 0;
}

Run

Sample Output

Enter an integer: 10
The number 10 is Even.
The number 10 is divisible by 2.
The number 10 is not divisible by 3.

Enter an integer: 9
The number 9 is Odd.
The number 9 is not divisible by 2.
The number 9 is divisible by 3.

Enter an integer: 7
The number 7 is Odd.
The number 7 is not divisible by 2.
The number 7 is not divisible by 3.

Stepwise Explanation

1. Include Header: The #include line brings in the input/output stream library, allowing the program to interact with the console. using namespace std; avoids repetitive typing of std::.
2. main Function: This is the entry point of every C++ program.
3. Declare Variable: An int variable named number is declared to store the integer input from the user.
4. Get User Input:
   • cout << "Enter an integer: "; displays a prompt on the screen.

1. Check Even/Odd:
   • if (number % 2 == 0): This condition uses the modulo operator. If the remainder of number divided by 2 is 0, the number is even.

1. Check Divisibility by 2:
   • Similar to the even/odd check, if (number % 2 == 0) determines if the number is exactly divisible by 2. This check logically overlaps with the even check but is included separately for clarity as requested.

1. Check Divisibility by 3:
   • if (number % 3 == 0): This condition checks if the remainder of number divided by 3 is 0. If true, the number is divisible by 3.

1. Return 0: return 0; indicates that the program executed successfully.

Conclusion

This article demonstrated a simple yet effective C++ program to determine if a given integer is even, odd, and divisible by 2 or 3. By leveraging the modulo operator and conditional statements, programmers can easily implement logic for categorizing numbers based on fundamental arithmetic properties.

Summary

• The modulo operator (%) is crucial for checking divisibility.
• A number N is even if N % 2 == 0; otherwise, it's odd.
• A number N is divisible by X if N % X == 0.
• Conditional if-else statements are used to execute specific code blocks based on these divisibility checks.
• These basic checks are foundational for many programming tasks involving numeric data.