# C Program to find union and intersection of two arrays

In this program, You will learn how to find union and intersection of two arrays in c.

1st is: 1 2 3 4 5

2nd list is: 3 4 5

Union is: 1 2 3 4 5

Intersection is: 3 4 5

## Example: How to find union and intersection of two arrays in c

Run it Now
``````#include<stdio.h>

void printUnion(int arr1[], int arr2[], int len1, int len2) {

int f, i, j, k = 0;
int arr3[100];

for (i = 0; i < len1; i++) {
arr3[k] = arr1[i];
k++;
}

for (i = 0; i < len2; i++) {
f = 0;
for (j = 0; j < len1; j++) {
if (arr2[i] == arr1[j]) {
f = 1;
}
}

if (f == 0) {
arr3[k] = arr2[i];
k++;
}
}
printf("\nUnion of Two Array is :");
for (i = 0; i < k; i++) {
printf("%d ", arr3[i]);
}
}

void printIntersection(int arr1[], int arr2[], int len1, int len2) {

int arr3[100];
int i, j, k = 0;

for (i = 0; i < len1; i++) {
for (j = 0; j < len2; j++) {
if (arr1[i] == arr2[j]) {
arr3[k] = arr1[i];
k++;
}
}
}
printf("\nIntersection of Two Array is :");
for (i = 0; i < k; i++) {
printf("%d ", arr3[i]);
}
}

int main() {

int arr1[100];
int arr2[100];
int arr3[100];
int i, j, len1, len2;

printf("Enter Size of 1st Array :");
scanf("%d", &len1);

printf("\nEnter 1st Array Elements :");
for (i = 0; i < len1; i++) {
scanf("%d", &arr1[i]);
}

printf("\nEnter Size of 2nd Array :");
scanf("%d", &len2);

printf("\nEnter 2nd Array Elements :");
for (i = 0; i < len2; i++) {
scanf("%d", &arr2[i]);
}

printUnion(arr1, arr2, len1, len2);
printIntersection(arr1, arr2, len1, len2);

return 0;
}
``````

#### Output:

``````Enter Size of 1st Array :5
Enter 1st Array Elements :1 2 3 4 5
Enter Size of 2nd Array :3
Enter 2nd Array Elements :3 4 5
Union of Two Array is :1 2 3 4 5
Intersection of Two Array is :3 4 5
``````