我试图在数组 c# 中找到最大的负数

Question

Running perfect but there is no result only cursor. The expected result is -15

        int[] dizi = { 4, 5, -15, 22, -34, 3, 0, 7, 43, 100 };
        int maxNumber = 0;

        for (int i = 0; i < dizi.Length; i++)
        {
            if (dizi[i] < 0)
            {
                if (maxNumber < dizi[i])
                {
                    maxNumber = dizi[i];
                    Console.WriteLine(maxNumber);
                }
            }
        }
        Console.ReadKey();

Answer 1

You can use Where and Max extension methods from System.Linq namespace:

var maxNegative = dizi.Where(x => x < 0).Max(); 
Console.WriteLine(maxNegative);

Max() will throw exception if there is not any negative number in the collection. So, you may want to use DefaultIfEmpty if you want to return 0 instead of any exception:

var maxNegative = dizi.Where(x => x < 0)
        .DefaultIfEmpty()
        .Max(); 

Answer 2

Use Max() to determine your desired value

int[] dizi = { 4, 5, -15, 22, -34, 3, 0, 7, 43, 100 };
int result = dizi.Where(x => x < 0).Max();

---

If you want to keep your code, replace int maxNumber = 0; with int maxNumber = int.MinValue; so maxNumber gets overwritten, otherwise there can't be a bigger negative number compared to 0

Answer 3

You can try this:

int maxNumber = 0;
    for (int i = 0; i < dizi.length; i++) {
        if (dizi[i] < 0) {
            if (maxNumber == 0 || dizi[i] > maxNumber ) {
                maxNumber = dizi[i];
            }
        }
    }
return maxNumber;

IDEONE DEMO

Answer 4

If you are looking for non-Linq solution (good old loop):

    int[] dizi = { 4, 5, -15, 22, -34, 3, 0, 7, 43, 100 };
    int maxNumber = 0;

    foreach (var item in dizi)
      if ((item < 0) && (maxNumber == 0 || item > maxNumber))
        maxNumber = item;

    Console.WriteLine(maxNumber);
    Console.ReadKey();

This code either prints out the maximum negative number -15 or 0 if the coolection ( dizi ) doesn't contain any negative numbers

Answer 5

我意识到 maxNumber 是否低于任何数组元素，例如int maxNumber=-100程序也能工作

Answer 6

Replace your code with this and you will get the correct output

   max=0;
   while(i<dizi.Length)
   {
      if(dizi[i]<max)
       max=dizi[i];
      i++;
   }
   if(max!=0)
   {
      Console.WriteLine(max);
   }
   else Console.WriteLine("No negative number")
 }