C++ Program to Check Whether Number is Even or Odd

Introduction

Determining whether a number is even or odd is a fundamental concept in programming, often explored when first learning a language like C++. This simple classification task involves checking the remainder of a number when divided by 2. If the remainder is zero, the number is even; otherwise, it's odd. This basic concept helps in understanding conditional statements and arithmetic operations in C++.

In this article, you will learn how to create a C++ program to check if a number is even or odd. Explore the implementation of this program through various examples, which include using conditional (if-else) statements and the ternary operator for different scenarios.

Implementing Basic Check with if-else

Before diving into specific examples, understand the foundational approach to determine the evenness or oddness of a number using conditional statements.

Basic Even/Odd Check

1. Prompt the user to input a number.

2. Use an if-else statement to determine if the number is even or odd.

   CPP

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   #include<iostream>
   using namespace std;
   
   int main() {
       int num;
       cout << "Enter an integer: ";
       cin >> num;
   
       if (num % 2 == 0) {
           cout << num << " is even." << endl;
       } else {
           cout << num << " is odd." << endl;
       }
       return 0;
   }

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   In this program:

   • The modulus operator % checks the remainder when num is divided by 2.
   • According to the condition num % 2 == 0, if the remainder is zero, it prints that the number is even; otherwise, it prints that the number is odd.

Utilizing the Ternary Operator

For a more concise implementation, the ternary operator can be used. This operator allows embedding the if-else logic directly into the output statement.

Compact Even/Odd Check Using Ternary Operator

1. Recognize that the ternary operator ?: can simplify the code.

2. Implement the even/odd check in a single line within the output command.

   CPP

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   #include<iostream>
   using namespace std;
   
   int main() {
       int num;
       cout << "Enter an integer: ";
       cin >> num;
   
       string result = (num % 2 == 0) ? "even" : "odd";
       cout << num << " is " << result << "." << endl;
       
       return 0;
   }

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   Here:

   • The expression (num % 2 == 0) ? "even" : "odd" directly computes whether num is even or odd. It assigns "even" or "odd" to the variable result based on the modulus operation.
   • This approach reduces the lines of code and enhances readability when conditions are simple.

Handling Multiple Numbers

Sometimes, the need arises to check the evenness or oddness of multiple numbers, such as in a list or array.

Multi-Number Check in Loops

1. Incorporate loops to handle the even/odd check across multiple numbers.

2. Array and loop usage can facilitate this process.

   CPP

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   #include<iostream>
   using namespace std;
   
   int main() {
       int numbers[] = {10, 23, 46, 57, 89};
       int size = sizeof(numbers) / sizeof(numbers[0]);
   
       for(int i = 0; i < size; i++) {
           cout << numbers[i] << " is " << ((numbers[i] % 2 == 0) ? "even" : "odd") << "." << endl;
       }
       return 0;
   }

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   In this iteration:

   • An array numbers of integer type is specified with five numbers.
   • A for-loop cycles through each element of the array and prints whether it is even or odd using the same ternary operator used previously.

Conclusion

Creating a C++ program to check if a number is even or odd is a basic yet crucial exercise to grasp handling conditional statements and arithmetic operations. Whether using traditional if-else structures or employing more succinct methods like the ternary operator, you equip yourself with versatile approaches to simple decision-making tasks in coding. Adapt these methods to enhance both functionality and readability in your programs, ensuring robust foundations for further C++ programming challenges.