JavaScript: Swap two halves of a given array of integers of even length

JavaScript Basic: Exercise-148 with Solution

Swap Halves of Even-Length Array

Write a JavaScript program to swap two halves of a given array of integers of even length.

Visual Presentation:

Sample Solution:

JavaScript Code:

/**
 * Function to swap the halves of an array
 * @param {Array} iarra - The input array
 * @returns {(boolean|Array)} - Swapped array if even length, otherwise false
 */
function halv_array_swap(iarra) {
  // Check if the array length is even
  if ((iarra.length % 2) !== 0) {
    return false; // Return false if the array length is odd
  }

  // Swap the halves of the array
  for (var i = 0; i < iarra.length / 2; i++) {
    var tmp = iarra[i]; // Temporary variable to store the current element
    iarra[i] = iarra[i + iarra.length / 2]; // Swap the first half with the second half
    iarra[i + iarra.length / 2] = tmp; // Swap the second half with the first half
  }
  return iarra; // Return the swapped array
}

// Test cases
console.log(halv_array_swap([1, 2, 3, 4, 5, 6])); // Output: [4, 5, 6, 1, 2, 3]
console.log(halv_array_swap([1, 2, 3, 4, 5, 6, 7])); // Output: false 

Output:

[4,5,6,1,2,3]
false

Live Demo:

See the Pen javascript-basic-exercise-148 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

/**
 * Function to swap the halves of an array
 * @param {Array} iarra - The input array
 * @returns {(boolean|Array)} - Swapped array if even length, otherwise false
 */
const halv_array_swap = (iarra) => {
  // Check if the array length is even
  if ((iarra.length % 2) !== 0) {
    return false; // Return false if the array length is odd
  }

  // Swap the halves of the array
  for (let i = 0; i < iarra.length / 2; i++) {
    // Use destructuring assignment for swapping elements
    [iarra[i], iarra[i + iarra.length / 2]] = [iarra[i + iarra.length / 2], iarra[i]];
  }

  return iarra; // Return the swapped array
};

// Test cases
console.log(halv_array_swap([1, 2, 3, 4, 5, 6])); // Output: [4, 5, 6, 1, 2, 3]
console.log(halv_array_swap([1, 2, 3, 4, 5, 6, 7])); // Output: false

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