Dynamic array implementation in C/C++

array.c

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

#define MAX(x, y) (((x) > (y)) ? (x) : (y))

ARRAY array_new(unsigned int size) {
    ARRAY s_array;
    
    s_array.ptr = malloc(size * sizeof(float));
    s_array.size = size;
    s_array.last_index = 0;
    return s_array;
}

void array_realloc(ARRAY*s_array, unsigned int size) {
    
    s_array->ptr = realloc(s_array->ptr, sizeof(size));
    s_array->size = size;
    if(s_array->last_index > size) {
        s_array->last_index = size;
    }
}

void array_free(ARRAY*s_array) {
    free(s_array->ptr);
    s_array->ptr = NULL;
    s_array->size = 0;
    s_array->last_index = 0;
}

bool array_is_empty(ARRAY s_array) {
    return s_array.last_index == 0;
}

bool array_is_full(ARRAY s_array) {
    return s_array.last_index == s_array.size;
}

void array_add(ARRAY*s_array, float item) {
    if(s_array->last_index < s_array->size) {
        s_array->ptr[s_array->last_index] = item;
        s_array->last_index++;
    } else {
        fprintf(stderr, "ERROR: %s.\n", "The array is full");
    }
}

float array_get(ARRAY*s_array, int index) {
    if(index < s_array->size) {
        return s_array->ptr[index];
    } else {
        fprintf(stderr, "ERROR: %s.\n", "Array index out of bounds");
        return 0;
    }
}

void array_set(ARRAY*s_array, int index, float item) {
    if(index < s_array->size) {
        s_array->ptr[index] = item;
        s_array->last_index = MAX(index+1, s_array->last_index);
    } else {
        fprintf(stderr, "ERROR: %s.\n", "Array index out of bounds");
    }
}

void array_printf(ARRAY s_array) {
    int i;
    
    printf("[");
    if(!array_is_empty(s_array)){
        printf("%f", s_array.ptr[0]);
        for(i=1; i<s_array.last_index; i++) {
            printf(", %f",s_array.ptr[i]);
        }
    }
    printf("]\n");
}

array.h

#ifndef ARRAY_H
#define	ARRAY_H

#include <stdbool.h>

typedef struct {
    unsigned int last_index;
    unsigned int size;
    float*ptr;
}ARRAY;

ARRAY array_new(unsigned int size);
void  array_realloc(ARRAY*s_array, unsigned int size);
bool  array_is_empty(ARRAY s_array);
bool  array_is_full(ARRAY s_array);
void  array_add(ARRAY*s_array, float item);
float array_get(ARRAY*s_array, int index);
void  array_set(ARRAY*s_array, int index, float item);
void  array_printf(ARRAY s_array);
void  array_free(ARRAY*s_array);

#endif

array_main_example.c

/* 
 * File:   main.c
 * Author: gustavo
 *
 * Created on 3 de junio de 2012, 22:27
 */

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

#include "array.h"
/*
 * 
 */
int main(int argc, char** argv) {

    ARRAY my_array;
    
    my_array = array_new(3);
    
    array_add(&my_array, 5);
    array_add(&my_array, 6);
    array_add(&my_array, 7);
    array_printf(my_array);
    
    array_add(&my_array, 8); // The array is full.
    
    array_realloc(&my_array, 7);
    array_add(&my_array, 8);
    array_add(&my_array, 9);
    
    array_printf(my_array);
    
    array_set(&my_array, 0, 5.5);
    array_add(&my_array, 10);
    
    array_printf(my_array);
    
    return (EXIT_SUCCESS);
}