long long int INT_MAX code example

Example 1: int max in c++

2147483647
  unsigned long long int = 18 446 744 073 709 551 615

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)