How to remove null values from an array in C++

In this tutorial, we will learn how to remove null values from an Array in C++. It is important to remove the null value for Memory Optimization,Efficient Data Processing, and Data Integrity purposes. Removing null values from arrays is a common task in C++ programming, especially in data processing and algorithm development

Approaches to remove null value from an array

• First, we create a new array where we store the values without null values.
• Then we copy values from the original array to our new array.
• When we found a null value then we skipped the value and shifted the non-null values.

Remove null values from an array in C++

#include <iostream>
using namespace std;
void removeNulls(int arr[], int& size) {
    int j = 0;
    for (int i = 0; i < size; ++i) {
        if (arr[i] != 0) { 
            arr[j++] = arr[i]; 
        }
    }
    size = j; 
}

int main() {
    int array[] = {1, 2, 0, 4, 0, 6, 0, 8};
    int size = sizeof(array) / sizeof(array[0]);
    cout << "Original array: ";
    for (int i = 0; i < size; ++i) {
        cout << array[i] << " ";
    }
    cout << endl;

    removeNulls(array, size);

    cout << "Array after removing nulls: ";
    for (int i = 0; i < size; ++i) {
        cout << array[i] << " ";
    }
    cout << endl;

    return 0;
}

Output:-

Original array: 1 2 0 4 0 6 0 8

Array after removing nulls: 1 2 4 6 8

 

Here we use “0” as a null value.

In this Code, you can see we are giving input [1,2,0,4,0,6,0,8], and we get output a [1,2,4,6,8] we easily remove the null values from the original array, here we use “0” as a null value.