Why am I getting these errors? Illegal start of expression

Question

Here's my code:

public class JavaApplication16 {
    public static void main(String[] args) {
       //illegal start of expression, ']' expected, <identifier> expected
       boolean a = groupSum(0, [2,4,8], 10); 
    }

    public boolean groupSum(int start, int[] nums, int target) {
        if (start >= nums.length) return (target == 0);

        if (groupSum(start + 1, nums, target - nums[start])) return true;
        if (groupSum(start + 1, nums, target)) return true;

        return false;
    }
}

I've tried to look for ways to fix this, but I am just so lost. Please help me debug my code.

try `boolean a = groupSum(0, new int[]{2,4,8}, 10);` and make the method `static`. — Ousmane D., Dec 24 '17 at 21:39
You get this error because this is not the correct syntax to define an array. — Turing85, Dec 24 '17 at 21:39
Here is answer for your next question: [Non-static method/variable cannot be referenced from a static context](https://stackoverflow.com/q/2559527) — Pshemo, Dec 24 '17 at 21:40

score 3 · Accepted Answer · answered Dec 24 '17 at 21:41

You are not using the correct notation to create an array. Creating an array of ints looks like: new int[]{1, 2, 3}. Another problem present in your code, is that you are calling a non-static method from a static context. You can fix this by labeling groupSum as static. Here is fixed version of your code:

class JavaApplication16 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        //illegal start of expression, ']' expected, <identifier> expected
        boolean a = groupSum(0, new int[]{2,4,8}, 10);
    }
    public static boolean groupSum(int start, int[] nums, int target) {
        if (start >= nums.length) return (target == 0);

        if (groupSum(start + 1, nums, target - nums[start])) return true;
        if (groupSum(start + 1, nums, target)) return true;

        return false;
    }
}

score 0 · Answer 2 · answered Dec 24 '17 at 21:39

0

Here's the correct way to work with int arrays.

boolean a = groupSum(0, new int[] {2, 4, 8}, 10);

answered Dec 24 '17 at 21:39

ReverseEffect

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Ahmad Al-Kurdi · Answer 3 · 2017-12-25T10:28:03.587

You need to change your code to be as the following

1- new int[]{2,4,8} to create array arrays of ints

2- change groupSum method to be static or create object form JavaApplication16 as the following JavaApplication16 ja16= new JavaApplication16(); ja16.groupSum(...);

You can do the following to fix your issues.

 public class JavaApplication16 {
            public static void main(String[] args) {
            boolean a = groupSum(0, new int[]{2,4,8}, 10);// new int[]{2,4,8} to create array of ints 
        }

        public static boolean groupSum(int start, int[] nums, int target) {// change the method to be static
            if (start >= nums.length) return (target == 0);

            if (groupSum(start + 1, nums, target - nums[start])) return true;
            if (groupSum(start + 1, nums, target)) return true;

            return false;
        }

}

Code-only answers are discouraged. Please add some explanation to your answer to clarify what is wrong and how to prevent/fix the problem. — Turing85, Dec 24 '17 at 21:42

Waleed Mortaja · Answer 4 · 2017-12-24T22:05:15.573

you have to define the int array as

boolean a = groupSum(0, new int[] {2,4,8}, 10);

another thing, The method groupSum is an instance method, while main is a static method; you cant use instance method inside a static mehod.

You have two solutions for this:

Define the groupSum method as static.

Create object of your class JavaApplication16 and use its method. The code would be like:

public class JavaApplication16 { 
 public static void main(String[] args) {
   JavaApplication16 ja16 = new JavaApplication16();
   boolean a = ja16.groupSum(0, new int[] {2,4,8}, 10); 
 }

 public boolean groupSum(int start, int[] nums, int target) { 
  if (start >= nums.length) return (target == 0); 
  if (groupSum(start + 1, nums, target - nums[start])) return true; 
  if (groupSum(start + 1, nums, target)) return true;

  return false; 
 } 
}

Why am I getting these errors? Illegal start of expression

4 Answers4