I need help regarding to this message:
char_cards.cpp: In member function 'void CHARACTER::Cards_pullout()': char_cards.cpp:88: warning: comparison between signed and unsigned integer expressions
Can somone explain what this error means? I think the problem is with DWORD but i don't know what is wrong.
This is the function:
DWORD CHARACTER::GetEmptySpaceInHand()
{
for (int i=0; i<MAX_CARDS_IN_HAND; ++i)
{
if (character_cards.cards_in_hand[i].type == 0)
return i;
}
return -1;
}
void CHARACTER::Cards_pullout()
{
DWORD empty_space = GetEmptySpaceInHand();
if (empty_space == -1) // Here is the error.
{
#ifdef __MULTI_LANGUAGE_SYSTEM__
ChatPacket(CHAT_TYPE_INFO, LC_TEXT(GET_LANGUAGE(this), "You don't have space in hands."));
#else
ChatPacket(CHAT_TYPE_INFO, LC_TEXT("You don't have space in hands."));
#endif
return;
}
RandomizeCards();
SendUpdatedInformations();
}
Initializing an unsigned integer to -1
is well defined and sets the unsigned integer to its maximal value. So using -1 to represent an error condition is OK. To get rid of the warning, you have few options:
1) Use a static_cast
. This indicates that you are aware of the conversion and it is intentional:
if empty_space == static_cast<DWORD>(-1)) { ...
2) Use std::numeric_limits<DWORD>::max()
instead of -1
. This will require including the limits
header.
if (empty_space == std::numeric_limits<DWORD>::max()) { ...
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.