Program to sort a given unsorted array in wave form in C++

C++ program to sort a given unsorted array of integers, in a waveform

Given:  An unsorted array of integers, we have to sort the array into a wave-like array. 

An array array[0….n-1] is sorted in wave form if array[0] >= array[1] <= array[2] >= array[3] <= array[4] >= array[5]…

Example:

Input: {4, 12, 15, 2, 20, 30, 21}

Output: {4 2 15 12 21 20 30}

# Algorithm

  1. Take an array input.
  2. Sort the array using sort() function.
  3. Elements are swapped to get the array in wave form.

Code:

#include<iostream>
#include<algorithm>
using namespace std;

void swap(int * p, int * q){ int temp = * p;

  • p = * q;
  • q = temp; }

void array_in_wave(int array[], int n){ sort(array, array + n); for (int i = 0; i < n - 1; i += 2) swap( & array[i], & array[i + 1]); }

int main(){ int array[100], n, i; cout << "Enter number of elements: "; cin >> n; cout << "\nEnter elements: ";

for (i = 0; i < n; i++) cin >> array[i];

cout << "Original array: ";

for (int i = 0; i < n; i++) cout << array[i] << " ";

array_in_wave(array, n);

cout << "\nWave form of the array is: ";

for (int i = 0; i < n; i++) cout << array[i] << " ";

return 0; }