Merge branch '10-add-is-empty-function' into 'main'

Resolve "Add is empty function"

Closes #10

See merge request !19

stack.c

 #include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+
 #include "stack.h"
 
 
@@ -75,3 +78,13 @@ int get_length(stack s) {
     return s.top + 1;
 }
 
+/**
+ * @brief Check if a stack is empty
+ * 
+ * @param s
+ * @return bool - true if stack is empty, false otherwise
+ */
+bool stack_is_empty(stack s)
+{
+    return s.top == -1;
+}
\ No newline at end of file

stack.h

 #ifndef _STACK_H_
 #define _STACK_H_
 
-
 typedef struct _stack {
     int *data;
     int capacity;
@@ -17,6 +16,7 @@ void stack_pop(stack *s, int *value);
 void stack_peek(stack s, int *value);
 void stack_clone(stack s, stack *clone);
 int get_length(stack s);
+bool stack_is_empty(stack s);
 
 void stack_print(const stack s);