simple_vector.c

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

struct Vector_t { int* arr; int sz; int cap; };

typedef struct Vector_t Vector;

Vector*
vector_new(int sz, int cap)
{
  Vector* v = (Vector*)malloc(sizeof(Vector));
  if (v == NULL) 
  {
    return NULL;
  }
  v->sz  = sz;
  v->cap = cap;
  v->arr = malloc(sizeof(int) * cap);
  if (v->arr == NULL)
  {
    free(v);
    return NULL;
  }
  return v;
}

int
vector_expand(Vector* v)
{
    int new_cap = v->cap * 2;
    int* new_arr = (int*)malloc(sizeof(int)*new_cap);
    if (new_arr == NULL)
    {
      return -1;
    }
    memcpy(new_arr, v->arr, sizeof(int)*v->sz);
    free(v->arr);
    v->arr = new_arr;
    v->cap = new_cap;
    return 0;
}

void
vector_each(Vector* v, void (*fn)(int))
{
  int sz   = v->sz;
  int* arr = v->arr;
  for (int i = 0; i < sz; i++)
  {
      fn(arr[i]);
  }
}

int
vector_free(Vector* v)
{
    free(v->arr);
    free(v);
    return 0;
}

int
vector_append(Vector* v, int x)
{
  if (v->sz == v->cap) 
  {
    if (vector_expand(v) != 0)
    {
      return -1;
    }
  }
  v->arr[v->sz++] = x;
  return 0;
}

void
print_int(int x) { printf("%d\n", x); }

int
main(void) {
  Vector* v = vector_new(0, 1);
  if (v == NULL)
  {
    printf("could not allocate vector\n");
    return 1;
  }
  for (int i = 0; i < 10; i++)
  {
    if (vector_append(v, i * 10) != 0)
    {
      printf("error appending");
      return -1;
    }
  }
  vector_each(v, &print_int);
  printf("size: %d, capacity: %d\n", v->sz, v->cap);
  
  if (vector_free(v) != 0)
  {
    printf("could not free vector");
    return 1;
  }  
  return 0;
}