Java Program to Find Missing Numbers in Array

This is a Java Program to Identify Missing Numbers in a Given Array.

We made a method as getMissingNo in which we pass the array and length of the array as arguments and using this method we calculate the missing number and hence we get the desired output.

Here is the source code of the Java Program to Identify Missing Numbers in a Given Array. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

  1. public class Missing
  2. {
  3.     static int getMissingNo (int a[], int n)
  4.     {
  5.         int i, total;
  6.      	total  = (n + 1) * (n + 2) / 2;
  7.      	for ( i = 0; i < n; i++)
  8.      	total -= a[i];
  9.      	return total;
  10.     }
  11.     public static void main(String... s)
  12.     {
  13.       	int a[ ] = {1, 2, 4, 5, 6};
  14.       	int miss = getMissingNo(a, 5);
  15.       	System.out.println("The number missing is :"+miss);
  16.     }
  17. }

Output:

$ javac Missing.java
$ java Missing
 
The number missing is :3

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Manish Bhojasia – Founder & CTO at Sanfoundry

I’m Manish, Founder & CTO at Sanfoundry, with 25+ years of experience across Linux systems, SAN technologies, advanced C programming, and building large-scale, performance-driven learning and certification platforms focused on clear skill validation.

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