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Remove Duplicates from an Array in C++

In this exercise, you will create a program that removes duplicates from an array of numbers. The function will iterate over the array and remove any duplicate values, leaving only the unique elements. This is a common problem in programming, as handling duplicate values efficiently is important in many real-world applications.

This exercise will help you practice working with arrays, utilizing loops and conditional statements to identify duplicates, and creating an efficient way to filter them out. It's a useful skill for data processing tasks such as cleaning data before analysis.

Group

Arrays and Vectors in C++

Objective

1. Define an array with some duplicate numbers.
2. Implement a function that iterates through the array and removes any duplicates.
3. Store the result in a new array or update the original array to only contain unique elements.
4. Output the new array after removing duplicates.
5. Test the program with different arrays to ensure it works correctly.

Create a program that removes duplicates from an array of numbers.

Example C++ Exercise

 Copy C++ Code 
#include <iostream> // Include iostream for input and output
#include <unordered_set> // Include unordered_set to easily track unique elements
using namespace std; // Use the standard namespace

// Function to remove duplicates from an array
void removeDuplicates(int arr[], int& size) {
    unordered_set<int> uniqueElements; // Declare a set to store unique elements
    int index = 0; // Variable to track position in the original array

    // Iterate through the array
    for (int i = 0; i < size; i++) {
        // If the element is not already in the set, add it
        if (uniqueElements.find(arr[i]) == uniqueElements.end()) {
            arr[index++] = arr[i]; // Assign the unique element to the current index
            uniqueElements.insert(arr[i]); // Insert the element into the set
        }
    }

    size = index; // Update the size of the array after removing duplicates
}

int main() {
    // Define an array with duplicates
    int arr[] = {1, 2, 2, 3, 4, 4, 5, 5, 6};
    int size = sizeof(arr) / sizeof(arr[0]); // Calculate the size of the array

    // Call the function to remove duplicates
    removeDuplicates(arr, size);

    // Output the array after removing duplicates
    cout << "Array after removing duplicates: ";
    for (int i = 0; i < size; i++) {
        cout << arr[i] << " "; // Print each element of the unique array
    }
    cout << endl;

    return 0; // End of program
}

 Output

Array after removing duplicates: 1 2 3 4 5 6

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