Question

What is wrong here? I want delete an item from an array, but it shows me

error ArrayIndexOutBound exception

public class delete {

    public static void main(String[]args) {
        int i;

        //delete  item from array
        int k[] = new int[]{77,99,44,11,00,55,66,33,10};

        //delete 55
        int searchkey=55;

        int nums=k.length;
        for ( i=0;i<nums;i++)
            if (k[i]==searchkey)
                break;

        for (int t=i;t<nums;t++)
            k[t]=k[t+1];
        nums--;

        for (int m=0;m<nums;m++) {
            System.out.println(k[m]);
        }
    }
}

Answer 1

The following rewriting should be instructive:

public class Delete {
    static int search(int key, int[] arr) {
        for (int i = 0; i < arr.length; i++)
            if (arr[i] == key) {
                return i;
            }
        return -1;
    }
    static void print(int[] arr, final int L) {
        for (int i = 0; i < L; i++) {
            System.out.println(arr[i]);
            // try this also:
            // System.out.format("%02d ", arr[i]);          
        }
    }
    public static void main(String[] args) {
        int nums[] = { 77, 99, 44, 11, 00, 55, 66, 33, 10 };
        final int N = nums.length;
        int searchKey = 55;

        int pos = search(searchKey, nums);
        for (int t = pos; t < N-1; t++) {
            nums[t] = nums[t + 1];
        }
        print(nums, N-1);
        // prints 77, 99, 44, 11, 0, 66, 33, 10
        System.out.println(010 == 8); // prints "true"
        System.out.println(00000); // prints "0
    }
}

Here are some key observations:

• Break apart logic into helper methods. This makes the logical components easier to test and reuse, and the overall logic easier to understand.
• It makes the code easier to understand if you use final local variables like N to denote the initial size of int[] nums, and define the rest of the logic in terms of N, N-1, etc.
  • The more non-final variables there are, the harder it is to understand what’s going on as their values changes over time
• Follow coding convention. In particular, class names starts with uppercase.
• Do be careful with the 00 in the array. The 0 prefix is for octal literals. That is, 010 == 8.
• Do note that 00 is printed as simple 0. Numerically, 00 = 000 = 0000 = 0. If you need this to be zero-padded, then that’s a formatting issue.

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See also

On octal literals

• 09 is not recognized where as 9 is recognized
• Integer with leading zeroes

On zero-padding

• Left padding integers with zeros in Java