Separating even and odd numbers in an array is a common task in programming. In this Answer, we will discuss how to separate odd and even numbers in a one-dimensional array. 

#include <iostream>
using namespace std;

int main() {

  // declare the array
  const int size = 10;
  int values[size] = {2, 3, 4, 6, 8, 5, 1, 10, 7, 9};
  // temporary variable to aid in swapping
  int temp;

  // for loop to iterate through the array
  for(int i = 0; i < size; i++)
  {
    // if current element is even, do nothing
    if(values[i] % 2 == 0)
    {
      continue;
    }
    // else if current element is odd, 
    // run another for loop to check 
    // every subsequent element in the array
    for(int j = i + 1; j < size; j++)
    {
      // if the subsequent element is even
      if(values[j] % 2 == 0)
      {
        // swap the current element and this subsequent element
        temp = values[i];
        values[i] = values[j];
        values[j] = temp;
      }
    }
  }
  // for loop to print array
  for(int i = 0; i < size; i++)
  {
    cout << values[i] << " ";
  }
  return 0;
}

# Explanation
1. First, declare your `int` array.
2. Run a `for` loop from `i = 0` to `i = size` to iterate through the array.
3. If the element is an even number, skip it.
4. If the element is an odd number, run another `for` loop inside the first loop. This nested `for` loop must run from the subsequent element to the end of the array (from `j = i + 1` to `j = size`). This `for` loop will check every subsequent element in the array to determine where the current element needs to be moved.
5. If the subsequent element is an even number, swap it with the current element. If the subsequent element is an odd number, nothing is required.
6. The `for` loop will run to the end of the array and keep swapping until the even and odd numbers are separated.

#include <iostream>

void segregate(int values[], int size) {
    int temp;

    // for loop to iterate through the array
    for (int i = 0; i < size; i++) {
        
        if (values[i] % 2 == 0) {
            continue;
        }

        for (int j = i + 1; j < size; j++) {
           
            if (values[j] % 2 == 0) {
                
                temp = values[i];
                values[i] = values[j];
                values[j] = temp;
            }
        }
    }
}


#include <iostream>

void segregate(int values[], int size) {
    int temp;

    // for loop to iterate through the array
    for (int i = 0; i < size; i++) {
        
        if (values[i] % 2 != 0) {        //update the if condition
            continue;
        }
        
        for (int j = i + 1; j < size; j++) {
           
            if (values[j] % 2 != 0) {    //update the if condition
                
                temp = values[i];
                values[i] = values[j];
                values[j] = temp;
            }
        }
    }
}





How to separate even and odd numbers in an array in C++

Iterate through the array, swapping odd and even numbers, so that odd numbers come first and even numbers follow.

How to separate even and odd numbers in an array in C++

Code

Explanation

Test yourself