C Sharp A pure implementation of push and pop functionality of string array

Here's a pure implementation of push and pop functionality of  string[] array in C Sharp, with timings. 


It does not use Queue<T> or Stack; 

For reference, Microsoft's own C# Stack implementation copies to an array! 

Here's a generalized version for objects C# Program to Implement Stack with Push and Pop Operations - Sanfoundry
Stack Data Structure Using Array and Linked List (codesdope.com)

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// Pushes an item to the top of the stack. // /// <include file='doc\Stack.uex' path='docs/doc[@for="Stack.Push"]/*' /> public void Push(T item) { if (_size == _array.Length) { T[] newArray = new T[(_array.Length == 0) ? _defaultCapacity : 2*_array.Length]; Array.Copy(_array, 0, newArray, 0, _size); _array = newArray; } _array[_size++] = item; _version++; }

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using System; namespace FixedLengthStackImplementationofStackofStringsArray { internal class Stack { static readonly int MAX = 3; //Max number of elements in string[] array int count; string[] stack = new string[MAX]; public Stack() //constructor { count = 1; //initialize stack with how many default values stack = new string[] { "x", "y", "z", "w" }; //w is ignored, no error given } public bool IsEmpty() { return (count == 0); } public bool IsFull() { return (count == MAX); } public int Length() { return MAX; } public int Count() { return count; } internal void Push(string data) { if (count > 0) { for (int i = 0; i <= MAX - 2; i++) //inline copy fast stack[i] = stack[i + 1]; stack[MAX - 1] = data; //always same place at top, which in this case is last element of array! if (count < MAX) count++; else Console.WriteLine("Max array size exceeded. Roll off the end."); Console.WriteLine("count=" + count + ", Push = " + data); } else { count++; stack[MAX - 1] = data; Console.WriteLine("count=" + count + ", Push = " + data); } } internal string Pop() { if (count > 0) count--; else return stack[MAX - 1]; string popValue = stack[MAX - 1]; //pop value on top of array Console.WriteLine("count = " + count + ", Pop = " + popValue); for (int i = MAX - 1; i >= 1; i--) //inline copy fast { stack[i] = stack[i - 1]; } stack[0] = "empty"; //initialize bottom of stack, gets empty string return popValue; } internal string Peek() //traditional definition of top { return stack[MAX - 1]; } internal string Top() { return stack[MAX - 1]; } internal void PrintTop() { Console.WriteLine("The topmost element of Stack is : {0}", stack[MAX - 1]); } internal void PrintStack() { Console.WriteLine("Printing Stack with {0} items:", count); for (int i = MAX - 1; i >= 0; i--) { Console.Write("arr[" + i + "]=" + stack[i] + ","); } Console.WriteLine(); Console.WriteLine(); } } public static class Program { public static void Main() { Stack s = new Stack(); Console.WriteLine("Pop/Push Array Test"); Console.WriteLine("Arr Len = " + s.Length().ToString()); Console.WriteLine("Top of stack is at index = " + (s.Length()-1).ToString()); s.PrintTop(); s.PrintStack(); s.Push("a"); s.PrintTop(); s.PrintStack(); s.Push("b"); s.PrintTop(); s.PrintStack(); s.Push("c"); s.PrintTop(); s.PrintStack(); s.PrintStack(); s.Push("d"); s.PrintTop(); s.PrintStack(); s.Push("e"); s.PrintStack(); s.PrintTop(); s.Push("f"); s.PrintStack(); s.PrintTop(); s.Push("g"); s.PrintStack(); s.PrintTop(); Console.WriteLine("Item popped from Stack : {0}", s.Pop()); s.PrintStack(); Console.WriteLine("Item popped from Stack : {0}", s.Pop()); s.PrintStack(); Console.WriteLine("Item popped from Stack : {0}", s.Pop()); s.PrintStack(); Console.WriteLine("Item popped from Stack : {0}", s.Pop()); s.PrintStack(); Console.ReadKey(); } } }

1st version below
This investigates using Array.Copy as Microsoft's own C# solution for Stack implementation, but is slow, compared to method above.

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using System;using System.Diagnostics;using System.Linq;public static class Program { public static void PushStringCopyArray(ref string[] array, string pushvalue) { string[] temp = new string[array.Length]; temp[0] = pushvalue; Array.Copy(array, 0, temp, 1, array.Length - 1); array = temp; } public static void PushStringArray(ref string[] array, string pushvalue) { int newLength = array.Length; string[] temp = new string[array.Length]; temp[0] = pushvalue; //push new value on top of array for (int i = 0; i < array.Length - 1; i++) temp[i + 1] = array[i]; array = temp; } /// <summary> /// Pop value from top of string[] ref array /// </summary> public static string PopStringArray(ref string[] array) { int newLength = array.Length; //string[] temp = new string[array.Length]; //default value is "" string[] temp = Enumerable.Repeat("#", array.Length).ToArray(); //set a default value string popvalue = array[0]; ////push new value on top of array for (int i = array.Length - 1; i >= 1; i--) temp[i - 1] = array[i]; array = temp; return popvalue; } public static void PrintArray(ref string[] array) { for (int i = 0; i < array.Length; i++) Console.Write("a[" + i + "]=" + array[i] + ","); Console.WriteLine(); Console.WriteLine(); } public static void Main() { Stopwatch sw = new Stopwatch(); string[] test = new string[] {"z","a","b","c"}; Console.WriteLine("Pop/Push Array Test"); Console.WriteLine("Arr Len=" + test.Length); PrintArray(ref test); PushStringArray(ref test, "1st"); PrintArray(ref test); PushStringArray(ref test, "2nd"); PrintArray(ref test); PushStringArray(ref test, "3rd"); PrintArray(ref test); sw.Start(); PushStringArray(ref test, "4th"); sw.Stop(); Console.WriteLine(sw.ElapsedTicks + " ticks. WOW! For loop, but still O(n)."); PrintArray(ref test); sw.Start(); PushStringCopyArray(ref test, "5th"); sw.Stop(); Console.WriteLine(sw.ElapsedTicks + " ticks. Array.Copy: I thought this would be better."); PrintArray(ref test); Console.WriteLine(PopStringArray(ref test)); PrintArray(ref test); Console.WriteLine(PopStringArray(ref test)); PrintArray(ref test); Console.WriteLine(PopStringArray(ref test)); PrintArray(ref test); Console.WriteLine(PopStringArray(ref test)); PrintArray(ref test); Console.WriteLine(PopStringArray(ref test)); PrintArray(ref test); } }