The Stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. In a stack, elements are inserted and removed from the same end, which is called the top.
The basic operations that can be performed on a stack are:
init: Initializes the stack.push: Inserts an element at the top of the stack.pop: Removes and returns the element at the top of the stack.peek: Returns the element at the top of the stack without removing it.isEmpty: Checks if the stack is empty.isFull: Checks if the stack is full.cleanup: Clears the stack.
To use the stack implementation, you need to include the stack.h header file in your program:
#include "stack.h"You can push elements into the stack using the push function:
push(&stack, 10);
push(&stack, 20);
push(&stack, 30);You can check if the stack is empty using the isEmpty function:
if (isEmpty(&stack)) {
// The stack is empty.
} else {
// The stack is not empty.
}You can get the element at the top of the stack without removing it using the peek function:
int top = peek(&stack);
if (top != -1) printf("The top of the stack is %d.\n", top);You can remove the element at the top of the stack using the pop function:
int value = pop(&stack);
if (value != -1) printf("The removed element is %d.\n", value);Finally, you can clear the stack using the cleanup function:
cleanup(&stack);Here is an example usage of the stack implementation in C:
#include <stdio.h>
#include "stack.h"
int main() {
Stack stack;
init(&stack);
// Test pushing and peeking items
push(&stack, 10);
push(&stack, 20);
push(&stack, 30);
printf("Peek: %d\n", peek(&stack)); // Should print 30
// Test popping items
int item = pop(&stack);
printf("Popped item: %d\n", item); // Should print 30
printf("Peek after pop: %d\n", peek(&stack)); // Should print 20
// Test checking if stack is empty
printf("Is empty: %d\n", isEmpty(&stack)); // Should print 0 (false)
pop(&stack);
pop(&stack);
printf("Is empty: %d\n", isEmpty(&stack)); // Should print 1 (true)
// Test cleaning up the stack
cleanup(&stack);
return 0;
}The maximum size of the stack is defined by the constant MAX_SIZE in the stack.h header file.