C++ Exercises: Create an array of odd numbers and specific lengths from an array

Last update on April 07 2025 12:57:28 (UTC/GMT +8 hours)

Create Array of Odd Numbers with Specific Length

Write a C++ program that creates a new array of odd numbers with specific lengths from a given array of positive integers.

Test Data:
({1,2,3,5,7,9,10},3) -> {1,3,5}

Sample Solution:

C++ Code :

#include <iostream>  // Including input-output stream header file
#include <string.h>  // Including string manipulation header file

using namespace std;  // Using standard namespace

int *odds;  // Declaration of an integer pointer variable

// Function to filter odd numbers from an array
int *test(int *nums, int n) {
    odds = new int[n];  // Allocating memory for 'odds' array

    int j = 0;  // Initializing variable 'j' to 0

    for (int i = 0; j < n; i++) {
        if (nums[i] % 2 != 0) {
            odds[j] = nums[i];  // Storing odd numbers in the 'odds' array
            j++;
        }
    }

    return odds;  // Returning the array containing odd numbers
}

// Main function
int main() {
    int nums[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};  // Initializing an array of integers
    int *result_array;  // Declaration of an integer pointer variable
    int arr_length = sizeof(nums) / sizeof(nums[0]);  // Calculating the length of the array

    // Displaying the original array elements
    cout << "Original array elements: " << endl;
    for (int i = 0; i < arr_length; i++) {
        std::cout << nums[i] << ' ';
    }

    int n = 3;  // Setting the length of the new array to store odd numbers
    odds = test(nums, n);  // Filtering odd numbers from 'nums' array and storing in 'odds' array
    cout << "\n\nNew array of odd numbers " << "(length = " << n << ")" << " from the said array: " << endl;

    // Displaying the new array containing odd numbers of specified length
    for (int i = 0; i < n; i++) {
        std::cout << odds[i] << ' ';
    }

    n = 5;  // Updating the length of the new array
    odds = test(nums, n);  // Filtering odd numbers from 'nums' array and storing in 'odds' array
    cout << "\n\nNew array of odd numbers " << "(length = " << n << ")" << " from the said array: " << endl;

    // Displaying the new array containing odd numbers of updated length
    for (int i = 0; i < n; i++) {
        std::cout << odds[i] << ' ';
    }

    delete[] odds;  // Deallocating memory allocated for 'odds' array
    return 0;  // Returning 0 to indicate successful completion of the program
}

Sample Output:

Original array elements:
1 2 3 4 5 6 7 8 9

New array of odd numbers (length = 3) from the said array:
1 3 5

New array of odd numbers (length = 5) from the said array:
1 3 5 7 9

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to extract the first n odd numbers from an input array of positive integers and store them in a new array.
Write a C++ program that reads an array and an integer n, then creates an array of the first n odd numbers encountered.
Write a C++ program to filter an integer array for odd numbers and output a new array containing the first n odd elements.
Write a C++ program that processes an array and returns a subarray of length n consisting solely of odd numbers.

C++ Code Editor:

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