#1::Stacks

IStack.cs

interface IStack {
    void Push(int value);
    int Pop();
    int Peek();
    bool IsFull();
    bool IsEmpty();
}

Stack.cs

class Stack : IStack {
    private int[] array;
    private int top;
    
    public Stack(int size) {
        this.array = new int[size];
        top = -1;
    }
    
    // Method implementations
}

StackExecution.cs

Stack stack1 = new Stack(3); //Initialization

stack1.Push(10);
stack1.ShowStack();

stack1.Push(30);
stack1.ShowStack();

stack1.Push(20);
stack1.ShowStack();

stack1.Push(50);
stack1.ShowStack(); //Throws the SystemException

StackMethods.cs

public void Push(int value) {
    if(this.IsFull()) { //Check if the stack is full
        throw new SystemException("Stack is already full!"); // Will not try to add new items
    }

    this.array[++top] = value;
}

public int Pop() {
    if(this.IsEmpty()) { // Check if the stack is empty
        throw new SystemException("Stack is empty!"); // Will not try to remove the top most item from the stack
    }

    return this.array[top--];
}

public int Peek() {
    if(this.IsEmpty()) { // Check if the stack is empty
        throw new SystemException("Stack is empty!"); // Will not try to get the top most item from the stack
    }

    return this.array[top];
}

public bool IsFull() {
    return (this.array.Length - 1) == this.top;
}

public bool IsEmpty() {
    return this.top == -1;
}

StackResult.sh

|  |
|  |
|10|
|__|

|  |
|30|
|10|
|__|

|20|
|30|
|10|
|__|

Unhandled Exception:
System.SystemException: Stack is already full!
  at Stack.Push (System.Int32 value) [0x0000b] in <6575c48c03074e1789a42989f3c57445>:0 
  at StackDemo.Main (System.String[] args) [0x00031] in <6575c48c03074e1789a42989f3c57445>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.SystemException: Stack is already full!
  at Stack.Push (System.Int32 value) [0x0000b] in <6575c48c03074e1789a42989f3c57445>:0 
  at StackDemo.Main (System.String[] args) [0x00031] in <6575c48c03074e1789a42989f3c57445>:0