Why does my Int value of an int array become 0 when it is higher than 10?-CodePudding

I wrote code which sorts the values of two arrays in ascending order and it actually works but only if I use values lower than 10 in the arrays. It actually sounds like a simple problem, but I already tried anything and I just don't understand why it isn't working.

First I should show you the merge function I wrote:

public static int[] merge(int[] leftArray, int[] rightArray){
    int[] result = new int[leftArray.length   rightArray.length];
    int position = 0;
    int left = 0;
    int right = 0;

    String result_debug;
    while(true){
        /*
        System.out.println("Result: "   result[position]);
        System.out.println("Left: "   leftArray[left]);
        System.out.println("Right: "   rightArray[right]);
         */
        if(leftArray[left] < rightArray[right]){
            result[position] = leftArray[left];

            position = position   1;
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            left  ;
        } else if (leftArray[left] > rightArray[right]) {
            result[position] = rightArray[right];
            position = position   1;
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            right  ;

        } else if (leftArray[left] == rightArray[right]) {
            result[position] = leftArray[left];
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            position = position   1;
            left  ;
            result[position] = rightArray[right];
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            position = position   1;
            right  ;
        }

        if(left == leftArray.length && right < rightArray.length) {

            for(int i = position; i < rightArray.length; i  ){
                result[i] = rightArray[right];
                System.out.println(rightArray[right]);
                right  ;
            }
            break;
        } else if (right == rightArray.length && left < leftArray.length) {

            for(int i = position; i < leftArray.length; i  ){
                result[i] = leftArray[left];
                System.out.println(leftArray[left]);
                left  ;
            }
            break;
        } else if (left == leftArray.length && right == rightArray.length) {

            break;


        }

        //System.out.println("Result: "   result[position]);
        //System.out.println("Left: "   leftArray[left]);
        //System.out.println("Right: "   rightArray[right]);
    }


    System.out.println("Result: "   result[result.length - 1]);
    
    return result;
}

Anytime I use arrays with values below 10, it works just perfectly, but when I use anything higher it becomes 0. As you can see I already tried some debugging methods but without success. I also wrote a function to make an int array into a String to print it out I can show you that function too:

public static String arrayToString(int[]arr){
    String result = "["   arr[0];

    for(int i = 1; i < arr.length; i  ){
        result = result   ", "   arr[i];
    }
    result  = "]";
    return result;
}

I also thought it could be because of the arraytoString method, but as you can see at the bottom of my merge method, I already checked that and the output is still 0, so it isn't because of that.

I don't think that it is a logic problem because as I said as long as I use values below 10 it works and also, at the beginning when I programmed it, it didn't even work with values higher than 8 it later began to work with 9 and 10.

I am using Windows 10 Pro.

CodePudding user response：

the problem is not with array values, but rather with the placement of values in the two arrays. the problem will be manifested with the input

    int[] a = {1,2,3};
    int[] b = {4,5,6};
    int[] c = merge(a, b);

you should learn how to use debugger. then you can debug your code properly. The problem is that the first item in array b is larger than all items in array a. so you populate result with all items from a and advance left (and also position) until left is equal to leftArray.length.

in the above example, at this point, both left and position are equal 3 .

at that point you enter this if statement: if(left == leftArray.length && right < rightArray.length) {
you assign i to start with value position. making it equal to rightArray.length and thus you do not copy over array b.

CodePudding user response：

I am not really sure what exactly was the point which solved it but after some experimenting my Code runs as it should just the last value of the result array had to be placed outside the loop. The working Code is:

   public static int[] merge(int[] leftArray, int[] rightArray){
    int[] result = new int[leftArray.length   rightArray.length];
    int position = 0;
    int left = 0;
    int right = 0;

    String result_debug;
    while(true){
        /*
        System.out.println("Result: "   result[position]);
        System.out.println("Left: "   leftArray[left]);
        System.out.println("Right: "   rightArray[right]);
         */
        if(leftArray[left] < rightArray[right]){
            result[position] = leftArray[left];

            position = position   1;
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            left  ;
        } else if (leftArray[left] > rightArray[right]) {
            result[position] = rightArray[right];
            position = position   1;
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            right  ;

        } else if (leftArray[left] == rightArray[right]) {
            result[position] = leftArray[left];
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            position = position   1;
            left  ;
            result[position] = rightArray[right];
            result_debug = arrayToString(result);
            System.out.println(result_debug);
            position = position   1;
            right  ;
        }

        if(left == leftArray.length && right < rightArray.length) {

            for(int i = position; right < rightArray.length; i  ){
                result[i] = rightArray[right];
                System.out.println(rightArray[right]);
                right  ;
            }
            break;
        } else if (right == rightArray.length && left < leftArray.length) {

            for(int i = position; left < leftArray.length; i  ){
                result[i] = leftArray[left];
                System.out.println(leftArray[left]);
                left  ;
            }
            break;
        } else if (left == leftArray.length && right == rightArray.length) {

            break;


        }

        //System.out.println("Result: "   result[position]);
        //System.out.println("Left: "   leftArray[left]);
        //System.out.println("Right: "   rightArray[right]);
    }


    System.out.println("Result: "   result[result.length - 1]);
    if(leftArray[leftArray.length - 1] > rightArray[rightArray.length - 1]){
        result[result.length - 1] = leftArray[leftArray.length - 1];
    }
    if(rightArray[rightArray.length - 1] > leftArray[leftArray.length - 1]){
        result[result.length - 1] = rightArray[rightArray.length - 1];
    }
    return result;
}

CodePudding user response：

Maybe you don't have to use a custom function:

int[] one = new int[]{59, 1, 523, -43, 123, 5};
int[] two = new int[]{3, 901, 73, -4783, 1, 53};

//merging the arrays
int[] merged = new int[one.length   two.length];
System.arraycopy(one, 0, merged, 0, one.length);
System.arraycopy(two, 0, merged, one.length, two.length);

Arrays.sort(merged);

System.out.println(arrayToString(merged));

Output: [-4783, -43, 1, 1, 3, 5, 53, 59, 73, 123, 523, 901]