C++ Vector Exercises: Vector elements smaller than its adjacent neighbours

C++ Vector: Exercise-2 with Solution

Write a C++ program that returns the elements in a vector that are strictly smaller than their adjacent left and right neighbours.

Sample Data:
({7, 2 ,5, 3, 1, 5, 6}) -> 2, 1
({1, 2 ,5, 0, 3, 1, 7}) -> 0, 1

Sample Solution:

C++ Code:

#include <algorithm>    // Including the Algorithm Library for certain functions like sort
#include <iostream>     // Including the Input/Output Stream Library
#include <vector>       // Including the Vector Library for using vectors

using namespace std;    // Using the Standard Namespace

// Function to find elements in the vector that are smaller than both adjacent neighbors
std::vector<int> test(std::vector<int> nums)
{
    std::vector<int> temp; // Initializing an empty vector to store elements that meet the condition
    for(int i=1; i<nums.size()-1; i++) {
        // Checking if the current element is smaller than both its previous and next elements
        if(nums[i] < nums[i-1] && nums[i] < nums[i+1]) 
            temp.push_back(nums[i]); // If the condition is met, adding the element to the 'temp' vector
    }
    return temp; // Returning the vector containing elements smaller than their adjacent neighbors
}

// Main function
int main(){
    // Uncomment either of the following lines to test different sets of numbers

    // vector<int> nums = {7, 2 ,5, 3, 1, 5, 6}; // Test vector with non-matching elements
    vector<int> nums = {1, 2 ,5, 0, 3, 1, 7}; // Test vector with elements smaller than both adjacent neighbors

    cout << "Original Vector elements:\n";
    for (int x : nums)
        cout << x << " "; // Printing the elements of the original vector

    vector<int> result = test(nums); // Calling the test function to find elements smaller than both neighbors
    cout << "\nVector elements that are smaller than its adjacent neighbors:\n";   
    for (int y : result)
        cout << y << "\n"; // Printing the elements that meet the condition from the 'result' vector
}

Sample Output:

Original Vector elements:
1 2 5 0 3 1 7 
Vector elements that are smaller than its adjacent neighbors:
0
1

Flowchart:

C++ Code Editor:

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