Technology Lesson: arrays

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Monday, February 16, 2015

Java Program to Find Union of two Arrays

For example we have two sorted arrays a1[]={2,3,5,11} and a2[]={4,7,9} then union of a1 and a2 will be {2,3,4,5,7,9,11}. A Java program for finding union of two arrays is given below.

Also Read: Java Program to Find Smallest and Largest Element in an Array

Java Program to Find Union of two Arrays

import java.util.Scanner; //import Scanner class in our program

class demo
{
public static void main(String...s)
{
int i,j,n1,n2;
Scanner sc=new Scanner(System.in); //used to read from keyboard

System.out.print("Enter number of elements of first array:");
n1=sc.nextInt();
System.out.print("Enter number of elements of second array:");
n2=sc.nextInt();

int a1[]=new int[n1];
int a2[]=new int[n2];

System.out.print("
Enter elements of first array in ascending order:");
for(i=0;i<n1;++i)
a1[i]=sc.nextInt();

System.out.print("
Enter elements of second array in ascending order:");
for(i=0;i<n2;++i)
a2[i]=sc.nextInt();

i=j=0;
System.out.print("
Union of Arrays: ");
while(i<n1&&j<n2)
{
if(a1[i]<a2[j])
{
System.out.print(a1[i]+" ");
i++;
}
else
if(a2[j]<a1[i])
{
System.out.print(a2[j]+" ");
j++;
}
else
{
System.out.print(a1[i]+" ");
i++;
j++;
}
}

if(i<n1)
while(i<n1)
{
System.out.print(a1[i]+" ");
i++;
}

if(j<n2)
while(j<n2)
{
System.out.print(a2[j]+" ");
j++;
}

}
}