Find Missing Number in Array - Java Code

When you given the number 221,223,224 in a array this logic is not working

import java.util.Arrays;

public class findmissing {
public static void main(String[] args) {
int [] arr = {4,7,8,9,10,5,3,1};
Arrays.sort(arr);
for(int i = 0;i<arr.length-1;i++){
if(arr[i+1] != arr[i] + 1){
System.out.println("the missing Number is " + (arr[i] + 1));
}
}
}
}

what if there is 2 numbers is missing???

is there any other way to do this without using formula?

Easy method
Subscribed :)

What if the numbers are {32,33,34,36}

Why bro if we add 0 the output change?

This is also not proper approach to solve this problem becoz here overflows occur

you need to take care of overflow conditions when you use this method of solving .....so better go with XOR method to solve this......

This solution is not gonna work for all the cases,

int[] array1 = {3,0,1};
missingNumberInTheArray(array1);
}

private static void missingNumberInTheArray(int[] array1) {
int n = array1.length+1;
int sum = (n * (n+1)/2);
System.out.println(sum);

for(int i=0;i<array1.length;i++){
sum=sum-array1[i];
}

System.out.println("finalValue:"+sum);
}

expected output is 2
I am getting 6 as the output


it should be
int sum = (n * (n-1))/2; instead of int sum = (n * (n+1)/2);



Thanks

Sir why we are taking are.length+1 instead of arr.length

Easy to understand.... thanks

I will like a better explanation, how you define use (n * (n+1))/2 ?

One of the simplest solution , it works :-)