c maximum integer code example

Example 1: max size for int c

-2,147,483,648 to 2,147,483,647

Example 2: C largest unsigned int

The sizeof function will help you here.
  sizeof(data type) returns a size_t //Number of bytes whatever the input for sizeof takes

Example:
//This statement will return 2 or 4 (depending on your system)
  return sizeof(int)