Как найти все отрицательные элементы массива

Okay, so i need to find all the negative numbers of array and return them.I found the negative number, but how do i return them all? P.S yes i am a beginner.

public static void main(String[] args) {
        int [] array = {5,-1,6,3,-20,10,20,-5,2};
        System.out.println(findNumber(array));
    }




public static int findNumber(int[] sum) {
    int num = 0;
    for (int i = 0; i < sum.length ; i++) {
        if(sum[i] < num) {
            num = sum[i];
        }
    }
    return num;
}

asked Nov 15, 2016 at 20:45

Java 8 based solution. You can use stream to filter out numbers greater than or equal to zero

    public static int[] findNumber(int[] sum)
    {
        return Arrays.stream(sum).filter(i -> i < 0).toArray();
    }

answered Nov 15, 2016 at 20:52

There are multiple ways of doing this, if you just want to output all of the negative numbers easily you could do this:

public static void main(String[] args) {
    int [] array = {5,-1,6,3,-20,10,20,-5,2};
    ArrayList<Integer> negativeNumbers = findNumber(sum);
    for(Integer negNum : negativeNumbers) {
        System.out.println(negNum);
    }
}

public static ArrayList<Integer> findNumber(int[] sum) {
    ArrayList<Integer> negativeNumbers = new ArrayList<>();
    for (int i = 0; i < sum.length ; i++) {
        if(sum[i] < 0) {
          negativeNumber.add(sum[i]);
        }
    }
    return negativeNumbers;
}

answered Nov 15, 2016 at 20:52

You can modify your method to iterate through the array of numbers, and add every negative number you encounter, to a List.

public static List<Integers> findNegativeNumbers(int[] num) {
    List<Integers> negativeNumbers = new ArrayList<>();
    for (int i = 0; i < num.length; i++) {
        if(num[i] < 0) {
            negativeNumbers.add(num[i]);
        }
    }
    return negativeNumbers;
}

You could then print out the list of negative numbers from this method itself, or return the list with return to be printed in main.

answered Nov 15, 2016 at 20:57

You code is returning the sum of elements, but I understood that you wanted every negative number.
So, I assumed you want something like this:

public static void main(String[] args) {
  int [] array = {5,-1,6,3,-20,10,20,-5,2};
  Integer [] result = findNumbers( array );
  for( int i : result )
  {
    System.out.println( i );
  }
}
public static Integer[] findNumbers(int[] v) {
  List<Integer> list = new ArrayList<>();
  for (int i = 0; i < v.length ; i++) {
      if(v[i] < 0) {
          list.add(v[i]);
      }
  }
  return list.toArray( new Integer[0] );
}

Is it?

Best regards.

public static int[] findNum(int[] array)
{
    int negativeIntCount = 0;
    int[] negativeNumbers = new int[array.length];
    for(int i = 0; i < array.length; i++)
    {
        if(array[i] < 0)
        {
            negativeIntCount++;
            negativeNumbers[i] = array[i];
        }
    }

    System.out.println("Total negative numbers in given arrays is " + negativeIntCount);

    return negativeNumbers;
}

To display as an array in output :

System.out.println(Arrays.toString(findNum(array)));

To display output as space gaped integers :

for(int x : findNum(array))
{
    System.out.print(" " + x)
}

answered Oct 15, 2021 at 5:46

13   голосов , оценка 4.154 из 5