sort stack

stacksort.c

#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 100

typedef struct {
    int buffer[MAX_SIZE];
    int top;
} stack;

void init(stack* s) {
    s->top = -1;
}
int isEmpty(stack* s) {
    return s->top == -1;
}
int isFull(stack* s) {
    return s->top == MAX_SIZE - 1;
}
void push(stack* s, int val) {
    if (!isFull(s))
        s->buffer[++s->top] = val;
}
int pop(stack* s) {
    if (!isEmpty(s))
        return s->buffer[s->top--];
    return -1;
}
int peek(stack* s) {
    if (!isEmpty(s))
        return s->buffer[s->top];
    return -1;
}

void insert_element(stack* st, int element) {
    if (isEmpty(st) || element >= peek(st)) {
        push(st, element);
        return;
    }
    int top_element = pop(st);
    insert_element(st, element);
    push(st, top_element);
}

void sort(stack* st) {
    if (isEmpty(st)) {
        return;
    }
    int top_element = pop(st);
    sort(st);
    insert_element(st, top_element);
}

void printStack(stack* s) {
    if (isEmpty(s)) return;
    int temp = pop(s);
    printStack(s);
    printf("%d ", temp);
    push(s, temp); 
}


void merge_and_sort(stack* s, stack* p) {
	while(!isEmpty(p)) {
		push(s, pop(p));
	}
	sort(s);
	printf("merged stack sorted:\n ");
	printStack(s);
	printf("\n");
}
int main() {
	int n;
	printf("Enter the size of the stack:\n");
	scanf("%d", &n);
	printf("Enter a stack:\n");
	stack* s = (stack*) malloc(sizeof(stack));
	init(s);
	for(int i = 0; i < n; i++) {
		int elem;
		scanf("%d", &elem);
		push(s, elem);
	}
	printf("Stack: \n");
	printStack(s);
	printf("\n");

	printf("Enter the size of the stack:\n");
	scanf("%d", &n);
	printf("Enter a stack:\n");
	stack* p = (stack*) malloc(sizeof(stack));
	init(p);
	for(int i = 0; i < n; i++) {
		int elem;
		scanf("%d", &elem);
		push(p, elem);
	}
	printf("Stack: \n");
	printStack(p);
	printf("\n");

	merge_and_sort(s, p);
	return 0;
}