stiva implementata ca Vector structura de baza

stack-vector.c

/*
Laborator 3 - exercise 2 Stiva LIFO implementata ca vector

index: 0    1     2    3 .... MAX - 1

      [4]  [15]   [2]  [17] [].....

      stiva plina = top = MAX - 1
      stiva goala = top = -1
*/

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#define MAX 100

void stack_init(int *top) {

	*top = -1;
}

bool stack_is_empty(const int *top) {

     return *top == -1;
}

bool stack_is_full(const int *top) {

	return *top == MAX - 1;
}

/*--------------Operatii fundamentale---------------*/
//adauga un element in vaful stivei O(1)
//overflow: stiva plina --->afiseaza eroare si nu modifica stiva 
//top = -1
//5 (top=0)
//7 (top=1)
// 1 2 3 4 5 6 8 VARF
void push(int *stack, int *top, int key) {


	 if(*top == MAX - 1) {
   
        fprintf(stderr, "Err: overflow - stiva este plina\n");
	 	return;
	 } 

	 (*top)++;

	 stack[*top] = key;
}

//pop: scoate elementul din varful stive si ii returneaza cheia - O(1)
//undeflow: stiva este goala -> afiseaza eroare si returneaza  -1

int pop(int *stack, int *top) {

     if(*top == -1) {
     	fprintf(stderr, "Err: undeflow - stiva este empty\n");
     	return -1;
     }

     int key = stack[ *top ];
     (*top)--;

     return key;
}

/*returneaza varful stivei fara sa-l stearga*/
int peek(const int* stack ,const int *top) {

    if(*top == -1) {

    	fprintf(stderr, "err: stiva este goala");
    	return -1;
    }

    return stack[*top];
}


void stack_print(const int *stack, const int *top) {

     if(*top == -1) {

     	printf("STIVA ESTE GOALA! {} top = -1\n");
     	return;
     }

     printf("VARF -> ");

     for(int i = *top; i >= 0; i--) {

         printf("%d", stack[i]);

         if(i > 0) printf(" -> ");  
     }

     printf(" -> baza\n");

}

int main(int argc, char const *argv[])
{
//s->first : SLL

	 int stack[ MAX ];

	 int top;

	 stack_init( &top );

	 stack_print(stack, &top);

	 //push
	 push(stack, &top, 4);
	 push(stack, &top, 15);
	 push(stack, &top, 2);
	 push(stack, &top, 7);

	 printf("\nDupa push(4, 15, 2, 7): \n");

	 stack_print(stack, &top); /* 7 --> 2 ---> 15 ---> 4*/

	 printf("\nTOP = %d (NU STERGE)\n", peek(stack, &top)); /* 7 , nu STERGE */

	 printf("\npop() = %d\n", pop(stack, &top)); /* 7 */
	 printf("\npop() = %d\n", pop(stack, &top)); /* 2 */

	 stack_print(stack, &top); /* 15 ---> 4*/

	 	 printf("\nTOP = %d (NU STERGE)\n", peek(stack, &top)); /* 7 , nu STERGE */


	 push(stack, &top, 14);
	 printf("\nDupa push(14): \n");
	 stack_print(stack, &top); /* 14 ---> 15 ----> 4 */;

	 //GOLIRE STIVA; top revine la -1, nu este nevoie FREE
	 top = -1;
	 printf("\n Dupa golire: \n");
	 stack_print(stack, &top);

	 printf("TEST undeflow: \n");
	 pop(stack, &top);
	 pop(stack, &top);
	 pop(stack, &top);

	 printf("\nTEST overflow: \n");

	 for( int i = 0; i <= MAX; ++i ) {

	 	push(stack, &top, i); //ultimul push -->EROARE
	 }

	 stack_print(stack, &top);

	 	push(stack, &top, 1011); //ultimul push -->EROARE

	
	return 0;
}