Csharp/C Sharp/Language Basics/stackalloc

allocates 26 characters on the stack the for loop assigns alphabetic characters to each element

 
using System;
public unsafe class Starter {
    public static void Main() {
        char* pChar = stackalloc char[26];
        char* _pChar = pChar;
        for (int count = 0; count < 26; ++count) {
            (*_pChar) = (char)(((int)("A")) + count);
            ++_pChar;
        }
        for (int count = 0; count < 26; ++count) {
            Console.Write(pChar[count]);
        }
    }
}

Invalid Cast Exceptions with Implicit Operators

 

public class TestClass
{
    private MainClass MyMainClassObject;
   
    public TestClass()
    {
        MyMainClassObject = new MainClass();
    }
   
    public static implicit operator MainClass(TestClass Source)
    {
        return Source.MyMainClassObject;
    }
}
   
public class MainClass
{
    public static void Main()
    {
        object MyObject;
        MainClass MyMainClassObject;
   
        MyObject = new TestClass();
        MyMainClassObject = (MainClass)MyObject;
    }
}

stackalloc Demo

 
using System;
class MainEntryPoint {
    static unsafe void Main() {
        Console.Write("How big an array do you want? \n> ");
        string userInput = Console.ReadLine();
        uint size = uint.Parse(userInput);
        long* pArray = stackalloc long[(int)size];
        for (int i = 0; i < size; i++)
            pArray[i] = i * i;
        for (int i = 0; i < size; i++)
            Console.WriteLine("Element {0} = {1}", i, *(pArray + i));
    }
}

Use stackalloc to allocate memory for integer array

 
using System;
class TestStackallocApp
{
    unsafe public static void Foo(int* pa)
    {
        for (int* ip = pa; ip < (pa+5); ip++)
        {
            Console.WriteLine("value {0} at address: {1}", *ip, (int)ip);
        }
    }
   
    static void Main(string[] args)
    {
        unsafe
        {
            int* pa = stackalloc int[5];
            pa[0] = 12;
            pa[1] = 34;
            pa[2] = 56;
            pa[3] = 78;
            pa[4] = 90;
            Foo(pa);
        }
    }
}