Problem with binary search code.

Question

Whenever target is greater then max element same error occurs.

Code :
public class newcode {
static int binarySearch(int[] arr, int target){
int start = 0;
int end = arr.length;

while (start<=end){
int mid = start+(end-start)/2;

if (target<arr[mid]){
end = mid-1;
} else if (target>arr[mid]) {
start = mid+1;
} else {
return mid;
}
}
return -1;
}
public static void main(String[] args) {
int[] arr = {1,3,6,7,9,18};
System.out.println(binarySearch(arr, 20));
}
}

Output:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 6 out of bounds for length 6
at newcode.binarySearch(newcode.java:9)
at newcode.main(newcode.java:21)

Process finished with exit code 1

Answer 1

Try replacing "<=" with "<" in the line 6: "while(start<=end){}"?
This raises IndexOutOfRangeException becuz array index starts at 0, your array length is 6, and the last index is 5. You are trying to get the elements of a index that doesn't exist.

Answer 2

You should read the error, this will help you to find where you made a mistake and fix it!
Good luck.