programming-examples/c/Arrays/C Program to Find Union & Intersection of 2 Arrays.c

/*
 * C Program to Find Union & Intersection of 2 Arrays
 */
#include <stdio.h>
#define SIZE 5

void get_value(int arr[]);
void print_value(int arr[], int n);
void function_sort(int arr[]);
int find_intersection(int array1[], int array2[], int intersection_array[]);
int find_union(int array1[], int array2[], int union_array[]);

void main()
{
    int array1[SIZE], array2[SIZE], intersection_array[SIZE], union_array[SIZE*2];
    int num_elements;
    //input elements of Array1
    printf("\n Enter the elements of Array 1: n");
    get_value(array1);
    printf("\n\n Elements of Array 1: ");
    print_value(array1, SIZE);
    //Sort array 1
    function_sort(array1);
    printf("nnSorted elements of Array 1: ");
    print_value(array1, SIZE);
    //input elements of Array2
    printf("nnEnter the elements of Array 2: n");
    get_value(array2);
    printf("\n\n Elements of Array 2: ");
    print_value(array2, SIZE);
    //Sort array 2
    function_sort(array2);
    printf("\n\nSorted elements of Array 2: ");
    print_value(array2, SIZE);
    //Find Intersection
    num_elements = find_intersection(array1, array2, intersection_array);
    printf("\n\n Intersection is: ");
    print_value(intersection_array, num_elements);
    //Find Union
    num_elements = find_union(array1, array2, union_array);
    printf("\n\n Union is: ");
    print_value(union_array, num_elements);
}

void get_value(int arr[])
{
    int i, j;
    for (i = 0; i < SIZE; i++)
        {
            j = i + 1;
            printf("\n Enter element %d: ", j);
            scanf("%d", &arr[i]);
        }
}

void print_value(int arr[], int n)
{
    int i;
    printf("{ ");
    for (i = 0; i < n; i++)
        {
            printf("%d ", arr[i]);
        }
    printf("}");
}

void function_sort(int arr[])
{
    int i, j, temp, swapping;
    for (i = 1; i < size; i++)
        {
            swapping = 0;
            for (j = 0; j < size-i; j++)
                {
                    if (arr[j] > arr[j+1])
                        {
                            temp = arr[j];
                            arr[j] = arr[j + 1];
                            arr[j + 1] = temp;
                            swapping = 1;
                        }
                }
            if (swapping == 0)
                {
                    break;
                }
        }
}

int find_intersection(int array1[], int array2[], int intersection_array[])
{
    int i = 0, j = 0, k = 0;
    while ((i < size) && (j < size))
        {
            if (array1[i] < array2[j])
                {
                    i++;
                }
            else if (array1[i] > array2[j])
                {
                    j++;
                }
            else
                {
                    intersection_array[k] = array1[i];
                    i++;
                    j++;
                    k++;
                }
        }
    return(k);
}

int find_union(int array1[], int array2[], int union_array[])
{
    int i = 0, j = 0, k = 0;
    while ((i < SIZE) && (j < SIZE))
        {
            if (array1[i] < array2[j])
                {
                    union_array[k] = array1[i];
                    i++;
                    k++;
                }
            else if (array1[i] > array2[j])
                {
                    union_array[k] = array2[j];
                    j++;
                    k++;
                }
            else
                {
                    union_array[k] = array1[i];
                    i++;
                    j++;
                    k++;
                }
        }
    if (i == SIZE)
        {
            while (j < SIZE)
                {
                    union_array[k] = array2[j];
                    j++;
                    k++;
                }
        }
    else
        {
            while (i < SIZE)
                {
                    union_array[k] = array1[i];
                    i++;
                    k++;
                }
        }
    return(k);
}

/*
Enter the elements of Array 1:

Enter element 1: 12

Enter element 2: 34

Enter element 3: 23

Enter element 4: 56

Enter element 5: 45


Elements of Array 1: { 12 34 23 56 45 }

Sorted elements of Array 1: { 12 23 34 45 56 }

Enter the elements of Array 2:

Enter element 1: 34

Enter element 2: 56

Enter element 3: 12

Enter element 4: 78

Enter element 5: 66


Elements of Array 2: { 34 56 12 78 66 }

Sorted elements of Array 2: { 12 34 56 66 78 }

Intersection is: { 12 34 56 }

Union is: { 12 23 34 45 56 66 78 }