Question

A stack, named ClrStack, contains records of some colors. Each record is represented as a tuple containing four elements — ColorName, RED, GREEN, BLUE. ColorName is a string, and RED, GREEN, BLUE are integers. For example, a record in the stack may be ('Yellow', 237, 250, 68).

Write the following user-defined functions in Python to perform the specified operations on ClrStack:

(i) push_Clr(ClrStack, new_Clr): This function takes the stack ClrStack and a new record new_Clr as arguments and pushes this new record onto the stack.

(ii) pop_Clr(ClrStack): This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow".

(iii) isEmpty(ClrStack): This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.

Hint:

Use append() to push, pop() to remove the top element,
and always check length before popping to avoid errors.

Answer 1

(i) push_Clr():

def push_Clr(ClrStack, new_Clr):
    ClrStack.append(new_Clr)
    print("New color record pushed to stack.")

This function adds `new_Clr` to the end of `ClrStack` using the `append()` method and prints a confirmation.

(ii) pop_Clr():

def pop_Clr(ClrStack):
    if len(ClrStack) == 0:
        print("Underflow")
        return None
    else:
        return ClrStack.pop()

This function checks if `ClrStack` is empty. If it is, it prints "Underflow" and returns `None`. Otherwise, it removes and returns the top element.

(iii) isEmpty():

def isEmpty(ClrStack):
    if len(ClrStack) == 0:
        return True
    else:
        return False

This function returns `True` if `ClrStack` is empty (length is zero), and `False` otherwise.