Authors: Victor Egele (vegele93@gmail.com) and Constance Amatey (consamate57@gmail.com)
In computer science, LIFO (Last-In-First-Out) and FIFO (First-In-First-Out) are two common data structures used to manage collections of elements. They are fundamental concepts in data processing and memory management.
A stack is a linear data structure that follows the LIFO principle, meaning that the last element added is the first to be removed. Stacks are used to manage function calls, expression evaluation, and memory management. A queue is a linear data structure that follows the FIFO principle, where the first element added is the first to be removed. Queues are used in scenarios such as scheduling, breadth-first search, and printing tasks.
The project involves implementing a stack and queue data structure using the Monty scripting language. This language uses opcodes to perform operations on the stack. The most common implementations of stacks and queues are using arrays or linked lists.
- Stacks: Used for implementing function calls and recursion tracking, expression evaluation (postfix notation), backtracking in algorithms, and managing memory in a limited environment.
- Queues: Used in scheduling tasks, breadth-first search algorithms, handling requests in real-time systems, and managing tasks in print spooling.
To compile the Monty project, use the following command:
$ gcc -Wall -Werror -Wextra -pedantic -std=c89 *.c -o monty
Implement the push
and pall
opcodes.
The push opcode
The opcode push
pushes an element to the stack.
- Usage:
push <int>
- where
<int>
is an integer
- where
- if
<int>
is not an integer or if there is no argument given to push, print the error messageL<line_number>: usage: push integer
, followed by a new line, and exit with the statusEXIT_FAILURE
- where is the line number in the file
- You won’t have to deal with overflows. Use the
atoi
function
The pall opcode
The opcode pall
prints all the values on the stack, starting from the top of the stack.
- Usage
pall
- Format: see example
- If the stack is empty, don’t print anything
Implement the pint
opcode.
The pint opcode
The opcode pint prints the value at the top of the stack, followed by a new line.
- Usage:
pint
- If the stack is empty, print the error message
L<line_number>: can't pint, stack empty
, followed by a new line, and exit with the statusEXIT_FAILURE
Implement the pop
opcode.
The pop opcode
The opcode pop
removes the top element of the stack.
- Usage:
pop
- If the stack is empty, print the error message
L<line_number>: can't pop an empty stack
, followed by a new line, and exit with the statusEXIT_FAILURE
Implement the swap
opcode.
The swap opcode
The opcode swap swaps the top two elements of the stack.
- Usage:
swap
- If the stack contains less than two elements, print the error message
L<line_number>: can't swap, stack too short
, followed by a new line, and exit with the statusEXIT_FAILURE
Implement the add
opcode.
The add opcode
The opcode add
adds the top two elements of the stack.
- Usage:
add
If the stack contains less than two elements, print the error messageL<line_number>: can't add, stack too short
, followed by a new line, and exit with the statusEXIT_FAILURE
- The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
- The top element of the stack contains the result
- The stack is one element shorter
Implement the nop
opcode.
The nop opcode
The opcode nop
doesn’t do anything.
- Usage:
nop