how to copy a array in C#-CodePudding

I try to take only positive numbers from the array and display them in the second array. I copy one array to another but at the output I get only 0. I’m a beginner in C#, so this is probably an easy thing to do

int[] array = { 12, 23, -22, -765, 43, 545, -4, -55, 43, 12, 351, -999, -87 };
        int[] positive = new int[array.Length];
        int positiveCounter = 0;
        int[] source = new int[7];
        Array.Copy(positive, source, 7);
        for (int i = 0; i < array.Length; i  )
        {
            if (array[i] > 0)
            {
                positive[positiveCounter] = array[i];
                positiveCounter  ;
            }
        }
        Console.WriteLine("Positive numbers are: ");
        foreach (var item in positive)
        {
            Console.WriteLine(item);
        }

CodePudding user response：

You can query initial array with a help of Linq:

using System.Linq;

...
int[] array = ...

int[] positive = array.Where(item => item > 0).ToArray();

To show positive array in one go you can try string.Join:

Console.WriteLine(string.Join(", ", positive));

You can solve the problem with a help of loops (no Linq solution):

int[] array = ...

int positiveCounter = 0;

foreach (int item in array)
  if (item > 0)
    positiveCounter  = 1;

int[] positive = new int[positiveCounter];

int index = 0;

for (int i = 0; i < array.Length;   i)
  if (array[i] > 0)
    positive[index  ] = array[i];

please note, that Array.Copy copies consequent items which is not guaranteed.

CodePudding user response：

As your request it will take all the positive number from 1st array and store in second array

 static void Main(string[] args)
    {
        ArrayList array =new ArrayList{ 12, 23, -22, -765, 43, 545, -4, -55, 43, 12, 351, -999, -87 };
        ArrayList array2 = new ArrayList { };
        foreach(int item in array)
        {
            Console.WriteLine(item);
            if (item > 0)
            {
                array2.Add(item);
            }
        }
        Console.WriteLine("-----------------------------");
        foreach (int item in array2)
        {
            Console.WriteLine(item);
        }
    }