Resizable Int Array imiplementation along with methods like map and filter.

myint.c

#include "myint.h"


struct myint* createEmpty()
{
    struct myint* newArray = (struct myint*) malloc(sizeof(struct myint));
    newArray->fullSize = 10;
    newArray->currentSize = 0;
    newArray->arr = (int*) malloc(10*sizeof(int));
    return newArray;
}

void push(struct myint* array, int number)
{
   if(array->currentSize == (array->fullSize))
   {
        // add a new guy
        int newSize = array->fullSize * 2;
        int *newArray = (int*) malloc(newSize * sizeof(int));
        for(int i = 0; i < (array->currentSize); i++)
        {
            newArray[i] = array->arr[i];
        }
        newArray[array->currentSize] = number;
        free(array->arr);
        array->arr = newArray;
        array->fullSize = newSize;
        array->currentSize++;
   }
   else
   {
        // just add simply
        array->arr[array->currentSize++] = number;
   }
}

struct myint* createFromIntArray(int* arr, int size)
{
    struct myint* newArray = createEmpty();
    for(int i = 0; i < size; i++)
    {
        push(newArray, arr[i]);
    }
    return newArray;
}

int atIndex(struct myint* array, int index)
{
    if(index > (array->currentSize - 1))
    {
        // raise an error
        printf("Error");
    }
    else
    {
        return array->arr[index];
    }
}

void print(struct myint* array)
{
    for(int i = 0; i < array->currentSize; i++)
    {
        printf("%d, ", array->arr[i]);
    }
    printf("\n");
}


struct myint* map(int (*func)(), struct myint* array)
{
   struct myint* newArray = createEmpty();
   for(int i = 0; i < array->currentSize; i++)
   {
       push(newArray, (*func)(array->arr[i])); 
   }
   return newArray;
}

struct myint* filter(int (*func)(), struct myint* array)
{
   struct myint* newArray = createEmpty();
   for(int i = 0; i < array->currentSize; i++)
   {
       if((*func)(array->arr[i]) == 1)
           push(newArray, array->arr[i]); 
   }
   return newArray;
}

myint.h

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

struct myint {
    int* arr;
    int fullSize; // keeps track of the total space we have
    int currentSize; // keeps track of the data that we stored currently
};

struct myint* createEmpty();
struct myint* createFromIntArray(int* arr, int size);
void push(struct myint* array, int number);
int atIndex(struct myint* array, int index);
void print(struct myint* array);
struct myint* map(int (*func)(), struct myint* array);
struct myint* filter(int (*func)(), struct myint* array);

test.c

#include "myint.h"

int square(int x)
{
    return x * x;
}

int isEven(int x)
{
    if (x%2==0)
        return 1;
    else
        return 0;
}
int main(void)
{
    int list[] = {1, 2, 3, 4, 5}; 
    struct myint* arr = createFromIntArray(list, 5); 
    struct myint* new = filter(isEven, arr);
    print(new);
    return 0;
}