C++ Program to Check for a Cube Number

Posted in C++ Tutorial

Updated on Oct 06, 2024

By Mari Selvan

👁️ 101 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, mathematical properties of numbers often lead to interesting and practical applications. One such property is being a cube number. A cube number is an integer that is the cube of an integer.

In this tutorial, we'll delve into a C++ program that efficiently checks whether a given number is a perfect cube or not.

📄 Example

Let's take a look at the C++ code that accomplishes this functionality.

isPerfectCube.cpp

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#include <iostream>
#include <cmath>

// Function to check if a number is a perfect cube
bool isPerfectCube(int number) {
  // Calculate the cube root of the number
  double cubeRoot = cbrt(number);

  // Check if the cube root is close to an integer
  return std::abs(cubeRoot - round(cubeRoot)) < 1e-10;
}

// Driver program
int main() {
  // Replace this value with your desired number
  int number = 27;

  // Check if the number is a perfect cube
  if (isPerfectCube(number)) {
    std::cout << number << " is a perfect cube.\n";
  } else {
    std::cout << number << " is not a perfect cube.\n";
  }

  return 0;
}

💻 Testing the Program

To test the program with different numbers, simply replace the value of the number variable in the main function.

Output

27 is a cube number.

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

🧠 How the Program Works

The program defines a function isPerfectCube that takes an integer as input and returns true if it is a perfect cube, and false otherwise.
Inside the function, it calculates the cube root of the number using the cbrt function from the <cmath> header.
It then checks if the cube root is close to an integer using a tolerance value (1e-10 in this case).
The main function initializes a variable with a number and calls the isPerfectCube function to determine if it's a perfect cube.

📏 Between the Given Range

Let's delve into the C++ code that checks and displays cube numbers in the specified range.

isCubeNumber.cpp

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#include <iostream>
#include <bits/stdc++.h>
// Function to check if a number is a cube number
bool isCubeNumber(int number) {
  int cubeRoot = cbrt(number); // cbrt() calculates the cube root
  return (cubeRoot * cubeRoot * cubeRoot == number);
}

// Driver program
int main() {
  std::cout << "Cube numbers in the range 1 to 50:" << std::endl;

  for (int i = 1; i <= 50; ++i) {
    if (isCubeNumber(i)) {
      std::cout << i << " ";
    }
  }

  std::cout << std::endl;

  return 0;
}

💻 Testing the Program

Output

Cube numbers in the range 1 to 50:
1 8 27

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

🧠 How the Program Works

The program defines a function isCubeNumber that takes an integer as input and checks if it is a cube number using the cbrt function, which calculates the cube root.
The main function iterates through numbers from 1 to 50 and prints those that are cube numbers.

🧐 Understanding the Concept of Cube Number

A cube number is the result of raising an integer to the power of 3. For example, 2 * 2 * 2 = 8, so 8 is a cube number.

🎢 Optimizing the Program

The provided program is straightforward, but you might consider optimizing it further. For instance, you can explore alternative methods for checking if a number is a cube number without using the cbrt function.

Feel free to incorporate and modify this code as needed for your specific use case. Happy coding!