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C++ Exercises: Sort a given unsorted array of integers, in wave form

C++ Array: Exercise-9 with Solution

Write a C++ program to sort a given unsorted array of integers, in wave form.
Note: An array is in wave form when array[0] >= array[1] <= array[2] >= array[3] <= array[4] >= . . . .

Sample Solution:

C++ Code :

#include<iostream>
#include<algorithm>
using namespace std;
 
void swap_elements(int *a, int *b)
{
    int t = *a;
    *a = *b;
    *b = t;
}
 
void array_wave(int nums[], int n)
{
    sort(nums, nums+n);
 
    for (int i=0; i<n-1; i += 2)
        swap_elements(&nums[i], &nums[i+1]);
}
 
int main()
{
    int nums[] = {4, 5, 9, 12, 9, 22, 45, 7};
    int n = sizeof(nums)/sizeof(nums[0]);
    cout << "Original array: ";
    for (int i=0; i < n; i++) 
    cout << nums[i] <<" ";
    array_wave(nums, n);
    cout << "\nWave form of the said array: ";
    for (int i=0; i<n; i++)
       cout << nums[i] << " ";
    return 0;
}

Sample Output:

Original array: 4 5 9 12 9 22 45 7 
Wave form of the said array: 5 4 9 7 12 9 45 22 

Flowchart:

Flowchart: Sort a given unsorted array of integers, in wave form

C++ Code Editor:

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Previous: Write a C++ program to find the next greater element of every element of a given array of integers. Ignore those elements which have no greater element.
Next: Write a C++ program to find the smallest element missing in a sorted array.

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C++ Programming: Tips of the Day

Can I assume (bool)true == (int)1 for any C++ compiler?

According to the standard, you should be safe with that assumption. The C++ bool type has two values - true and false with corresponding values 1 and 0.

The thing to watch about for is mixing bool expressions and variables with BOOL expression and variables. The latter is defined as FALSE = 0 and TRUE != FALSE, which quite often in practice means that any value different from 0 is considered TRUE.

A lot of modern compilers will actually issue a warning for any code that implicitly tries to cast from BOOL to bool if the BOOL value is different than 0 or 1

Ref: https://bit.ly/3PWhs5N