پشته (Stack)

MAXIMUM_STACK_SIZE = 1024

class Stack:
    def __init__(self): self.items = []
    def __str__ (self): 
        ws = []
        for i, item in enumerate(self.items[::-1]):
            if   i == 0                : ws.append(f"{item} <first")
            elif i == len(self.items)-1: ws.append(f"{item} <last") 
            else                       : ws.append(str(item))
        return "n".join(ws)
        
    def push(self, value): 
        if len(self.items) == MAXIMUM_STACK_SIZE-1: raise Exception("Stack overflow")
        self.items.append(value)    
    
    def pop(self, n=-1):
        if len(self.items) < n: raise Exception("Stack overflow")
        del self.items[n]

stack = Stack()

stack.push(2)
stack.push(4)
stack.push(1)

print(stack)

1 <اولی
4
2 <آخری

stack.pop()

print(stack)

4 <اولی
2 <آخری