Stacks, Queues - LIFO, FIFO

The goal of this project is to create an interpreter for Monty ByteCodes files. Monty 0.98 is a scripting language that is first compiled into Monty byte codes (Just like Python). It relies on a unique stack, with specific instructions to manipulate it.

Objectives:

This project reviewed the concepts of LIFO and FIFO methods, stacks, queues, linked lists, and global variables in C programming.

Monty byte code files examples:

Files containing Monty byte codes usually have the .m extension.

::~/monty $

push 0$
push 1$
push 2$
  push 3$
                   pall    $
push 4$
    push 5    $
      push    6        $
pall$

Monty byte code files can contain blank lines (empty or made of spaces only, and any additional text after the opcode or its required argument is not taken into account:

::~/monty $

push 0 Push 0 onto the stack$
push 1 Push 1 onto the stack$
$
push 2$
  push 3$
                   pall    $
$
$
                           $
push 4$
$
    push 5    $
      push    6        $
$
pall This is the end of our program. Monty is awesome!$

The Monty Program:

Usage: $ monty file. Where file is the path to the file containing Monty byte code.

Opcode	What it does:
push <int>	Pushes an element to the stack.
pall	Prints all the values on the stack, starting from top of the stack.
pint	Prints the value at the top of the stack, followed by a new line
pop	Removes the top element of the stack.
nop	Does nothing.
swap	Swaps the top two elements of the stack.
add	Adds the top two elements of the stack.
sub	Subtracts the top element of the stack from the second top element of the stack.
mul	Multiplies the second top element of the stack with the top of stack.
div	Divides the second top element of the stack by the top of stack.
mod	Computes the rest of the division of the second top element of the stack by the top element of the stack.
pchar	Prints the char at the top of the stack, followed by a new line.
pstr	Prints the string starting at the TOS, followed by a new line.
rotr	Rotates the stack to the bottom. The last element of the stack becomes the top element of the stack.
rotl	Rotates the stack to the top. The top element of the stack becomes the last one, and the second top element of the stack becomes the first one.
stack	Sets the format of the data to a stack (LIFO). This is the default behavior of the program.
queue	Sets the format of the data to a queue (FIFO).

Resources:

• How do I use extern to share variables between source files in C?
• Data Structures: Stacks & Queues
• CS50 2019 - Lecture 5 - Data Structures
• Doubly Circular Linked List | Set 1 (Introduction and Insertion)
• C library function - atexit()

Compilation:

Code files must be compiled this way:

$ gcc -Wall -Werror -Wextra -pedantic *.c -o monty

• Any output must be printed on stdout
• Any error message must be printed on stderr

Author:

• Tatiana Orejuela Zapata | Github

Foundations - Low-level programming & Algorithm Data structures and Algorithms

May, 2020. Cali, Colombia.