C++ Recursion: Maximum and minimum elements in an array

Last update on December 20 2024 12:31:36 (UTC/GMT +8 hours)

Write a C++ program to implement a recursive function to find the maximum and minimum elements in an array.

Sample Solution:

C Code:

// Recursive function to find the maximum  and minimum elements in an array
#include <iostream> // Including the Input/Output Stream Library

// Recursive function to find the maximum element in the array
int findMax(int nums[], int start, int end) {
  // Base case: when there is only one element, it is the maximum
  if (start == end)
    return nums[start];

  // Recursive case: divide the array in half and find the maximum in each half,
  // then return the maximum of the two halves
  int mid = (start + end) / 2;
  int max1 = findMax(nums, start, mid);
  int max2 = findMax(nums, mid + 1, end);

  return (max1 > max2) ? max1 : max2;
}

// Recursive function to find the minimum element in an array
int findMin(int nums[], int start, int end) {
  // Base case: when there is only one element, it is the minimum
  if (start == end)
    return nums[start];

  // Recursive case: Divide the array in half and find the minimum in each half,
  // then return the minimum of the two halves
  int mid = (start + end) / 2;
  int min1 = findMin(nums, start, mid);
  int min2 = findMin(nums, mid + 1, end);

  return (min1 < min2) ? min1 : min2;
}

int main() {
  int nums[] = { 9, 2, 4, 0, 2, 2, 3, 4, 5, 7 }; // Initializing an array with elements
  int size = sizeof(nums) / sizeof(nums[0]); // Calculating the size of the array

  std::cout << "Array elements: " << std::endl;
  // Loop through the array elements and display them
  for (size_t i = 0; i < size; i++) {
    std::cout << nums[i] << ' ';
  }

  // Find the maximum and minimum elements in the array using recursion
  int max = findMax(nums, 0, size - 1);
  int min = findMin(nums, 0, size - 1);

  std::cout << "\nMaximum element: " << max << std::endl; // Display the maximum element
  std::cout << "Minimum element: " << min << std::endl; // Display the minimum element

  return 0; // Returning 0 to indicate successful execution of the program
}

Sample Output:

Array elements:
9 2 4 0 2 2 3 4 5 7
Maximum element: 9
Minimum element: 0

Explanation:

In the above exercise,

• The "findMax()" function takes an array (nums), the starting index (start), and the ending index (end) as parameters.
• Use recursion to find the maximum element in the array.
• The base case is when there is only one element (start == end), in which case the function returns that element.
• In the recursive case, the function divides the array in half, finds the maximum in each half by recursively calling "findMax()", and returns the maximum of the two halves.
• Similarly, the "findMin()" function takes the same parameters and finds the minimum element in the array using a similar recursive approach.
• The "main()" function initializes an array, calculates its size, and then calls "findMax()" and "findMin()" to find the maximum and minimum elements, respectively.
• Finally, it displays the results.

Flowchart:

CPP Code Editor:

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