adding values to the array without initialization the length

When I can add values to the array , Exception occurs. In C# , can i set the values wit开发者_StackOverflow中文版hout initializing the array length.

int[] test;
test[0] = 10;

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No, if you want a data structure that dynamically grows as you Add items, you will need to use something like List<T>. Arrays are fixed in size.

When you have

int[] test;

you haven't instantiated an array, you've merely declared that test is a variable of type int[]. You need to also instantiate a new array via

int[] test = new int[size];

As long as size is positive then you can safely say

int[0] = 10;

In fact, you can say

int[index] = 10

as long as 0 <= index < size.

Additionally, you can also declare, instantiate and initialize a new array in one statement via

int[] test = new int[] { 1, 2, 3, 4 };

Note that here you do not have to specify the size.

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You can't do that with an array, per se, but you can use a List.

        List<int> test = new List<int>();
        test.Add(10);

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Only that way

int[] a = {10};

But the length of the array will be 1 after that.

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Try

int[] x = new int[] { 1, 2, 3, 4 };

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Use List<int> t = new List<int>() and use t.Add() method.

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you can use this way

string[] words;
words = new List<string>() { "hello","hi" }.ToArray()