sizeof operator _c language in the value of C-language security coding

In general, do not apply the sizeof operator to the pointer when getting the length of an array .

Now take a look at the following code:

void clear (int array[]) {for
  (size_t i = 0; i < sizeof (array)/sizeof (array[0)); i++) {
    array[i] = 0;
  }
}
void DoWork (void) {
  int dis[12];
  Clear (dis);
  /*...*/
}

Clear () uses sizeof (array)/sizeof (Array[0]) to determine the number of elements in this array, but since array is a parameter, it is a pointer type, sizeof (array) = sizeof (int *) = 4 (32-bit OS)

When the sizeof operator is applied to a parameter that declares an array or function type, it produces the length of the adjusted (pointer) type

The solution to this problem is as follows:

void clear (int array[], size_t len) {for
  (size_t i = 0; i < len; i++) {
    array[i] = 0;
  }
}
void DoWork (void) {
  int dis[12];
  Clear (Dis, sizeof (DIS)/sizeof (dis[0));
  /*...*/
}