C/C++ Stack

dynamic_stack.c

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    int *data;
    int capacity;
    int top;
} Stack;

void init(Stack *s) {
    s -> top = -1;
    s -> capacity = 1;
    s -> data = (int*)malloc(s -> capacity * sizeof(int));
}

int isEmpty(Stack *s) {
    return s -> top == -1;
};

int isFull(Stack *s) {
    return s -> top == (s -> capacity - 1);
};

void push(Stack *s, int value) {
    if(isFull(s)) {
        s -> capacity *= 2;
        s -> data = (int*)realloc(s -> data, s -> capacity * sizeof(int));
    }
    s->data[++(s->top)] = value;
}

int pop(Stack *s) {
    if(isEmpty(s)) return printf("Stack is empty..");
    else return s->data[(s->top)--];
}

int peek(Stack *s) {
    if(isEmpty(s)) return printf("Stack is empty..");
    else return s->data[(s->top)];
}

int main() {
    Stack s;

    init(&s);

    push(&s, 1);
    push(&s, 2);
    push(&s, 3);
    push(&s, 4);
    push(&s, 5);

    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek %d\n", peek(&s));

    return 0;
}

static_stack.c

#include <stdio.h>

#define MAX_STACK_SIZE 100

typedef struct {
    int arr[MAX_STACK_SIZE];
    int top;
} Stack;

void init(Stack *s) {
    printf("initialize stack...\n");
    s -> top = -1;
    printf("initiallize stack complete!\n");
}

int isEmpty(Stack *s) {
    return s -> top == -1;
};

int isFull(Stack *s) {
    return s -> top == (MAX_STACK_SIZE - 1);
};

void push(Stack *s, int value) {
    if(isFull(s)) printf("Stack is full...");
    else s->arr[++(s->top)] = value;
};

int pop(Stack *s) {
    if(isEmpty(s)) return printf("Stack is empty...");
    else return s->arr[(s->top)--];
};

int peek(Stack *s) {
    if(isEmpty(s)) return printf("Stack is empty...");
    else return s->arr[(s->top)];
};

int main() {
    Stack s;

    init(&s);

    push(&s, 1);
    push(&s, 2);
    push(&s, 3);
    push(&s, 4);
    push(&s, 5);

    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek: %d\n", peek(&s));

    printf("Pop: %d\n", pop(&s));
    printf("Peek %d\n", peek(&s));

    return 0;
};