```
int* findDisappearedNumbers(int* nums, int numsSize, int* returnSize) {
int m;
for (int c = 0; c < numsSize; c++) {
m = abs(nums[c]) - 1;
nums[m] = -1 * abs(nums[m]);
}
*returnSize = 0;
for (int c = 0; c < numsSize; c++)
if (nums[c] > 0)
(*returnSize)++;
int *ret = (int *) calloc (*returnSize, sizeof (int));
int s = 0;
for (int c = 0; c < numsSize; c++)
if (nums[c] > 0)
ret[s++] = c + 1;
return ret;
}
```