未定义引用（main.cpp 文件中出现错误）
Undefined Reference to (error coming in main.cpp file)
在 Code::Blocks 中尝试编译我的代码时，我收到一堆未定义的引用错误。代码如下。
Header
#ifndef BLACKJACK_GAME
#define BLACKJACK_GAME
// A game of blackjack has a deck and two hands
#include "Deck.h"
#include "BlackjackHand.h"
// Different ways the game can end. The first states take precedence over
// over the latter states so check for the early ones first (like blackjack)!
// Note that a "natural 21" is when you are delt two cards totaling 21.
enum eGameState {
GAME_BLACKJACK_PUSH, // Both player and dealer have a natural 21
GAME_DEALER_BLACKJACK, // Dealer has a natural 21
GAME_PLAYER_BLACKJACK, // Player has a natural 21
GAME_DEALER_BUST, // The dealer has more than 21
GAME_PLAYER_BUST, // The player has more than 21
GAME_DEALER_WIN, // The dealer's score is higher than players
GAME_PLAYER_WIN, // The player's score is higher than dealers
GAME_PUSH // The scores are tied
};
class BlackjackGame
{
public:
BlackjackGame();
// Clear the players hands and shuffle the deck
void newGame();
// Play a single round of blackjack showing the output using
// the 'PDcurses' library (for color and card suits).
void playGameCurses();
// Display the deck on the screen (for debugging purposes)
void printDeckCurses();
// Print both players hands to the screen using 'PDCurses'
// If pShowDealerScore is true then the dealer's score is printed
// Otherwise, the dealer's score is shown as '??'
void printHandsCurses(bool pShowDealerScore = false) const;
// Determine the state of the game. Note that if you have not yet
// played a round since you constructed this object or called newGame()
// Then the state returned is not accurate.
eGameState getGameState() const;
private:
// A deck of cards for shufflying and dealing hands
Deck mDeck;
// The two hands for the player and the dealer
BlackjackHand mPlayer, mDealer;
// A helper function for prompting the player (internal use only)
char promptPlayerCurses();
// A helper function to quit the game (internal use only)
void quitGameCurses();
};
#endif
CPP
#include "BlackjackGame.h"
// The library used for our text based user interface
#include <curses.h>
// Normal text color for PDCurses (defined in main)
#define NORM_TEXT 1
// Default constructor (does nothing)
BlackjackGame::BlackjackGame() {}
/* newGame() - Clear the two hands so we are ready for a new game */
void BlackjackGame::newGame()
{
mDealer.clear();
mPlayer.clear();
}
/* playGameCurses() - Play a single round of poker with one human player and one
* dealer following standard Vegas rules. Uses PDCurses for input and output to
* the console.
*
* You must implement this method but you do not need to worry about curses. Call
* 'promptPlayerCurses() to show the hands and prompt the human player to hit, stand
* or quit. This method will return the key they pressed. You can also use
* quitGameCurses() to exit properly if the user chose to 'quit'.
*/
void BlackjackGame::playGameCurses()
{
// TODO: Shuffle the deck and deal the cards (make sure dealer's first card is hidden).
mDeck.shuffle();
mPlayer.takeCard(mDeck.dealCard());
mDealer.takeCard(mDeck.dealCard());
mDealer.hideCard();
mPlayer.takeCard(mDeck.dealCard());
mDealer.takeCard(mDeck.dealCard());
// TODO: Check for a 'natural 21' (blackjack) before playing
if ( mDealer.hasBlackjack() || mPlayer.hasBlackjack())
quitGameCurses();
// TODO: Allower human player to hit, stand and quit as needed (repeat until player is done)
int flag = 0;
while(flag!=1)
{
char input = promptPlayerCurses(); // This line is an example only, a placeholder
switch(input)
{
case 'h': mPlayer.takeCard(mDeck.dealCard());
break;
case 's': flag =1;
break;
case 'q': quitGameCurses();
break;
default: break;
}
}
// TODO: Play the 'dealer' hand according to vegas rules
mDealer.showCards();
while(vegasDealerWouldHit())
{
mDealer.takeCard(mDeck.dealCard());
}
}
/* promptPlayerCurses() - Show the hands and prompt the human player to hit, stand or quit.
* output: returns the single character entered by the player at the prompt.
* - 'h' means hit, 's' means stand
* - 'q' means you should immediatly quit (call 'quitGameCurses()')
*/
char BlackjackGame::promptPlayerCurses()
{
// Show the hands
printHandsCurses();
// Hit or stand?
attron(COLOR_PAIR(NORM_TEXT));
mvprintw(3, 0, "Hit, stand or Quit ('h', 's', 'q'): ");
refresh();
// Read and return a single character
return getch();
}
/* quitGameCurses() - End curses output and exit the program immediately */
void BlackjackGame::quitGameCurses()
{
// End curses output, then pause and exit
endwin();
system("pause");
exit(0);
}
/* printDeckCurses() - A handy function that displays the content of the game deck
* using curses.
*
* This can be handy for debugging your deck and making sure it is getting properly
* shuffled. It is presently used for the fancy opening screen.
*/
void BlackjackGame::printDeckCurses()
{
// Start at the upper left corner of the screen
move(0, 0);
// For all 52 cards
for(int i=1; i<=52; i++)
{
// Get the next card and print it
PrintableCard lCard = mDeck.dealCard();
lCard.printCurses();
// If we've output 13 cards then move down a row
if(i%13 == 0)
{
move(2*(i/13), 0);
}
else
{
// Switch back to normal text color and output ' ' characters
attron(COLOR_PAIR(NORM_TEXT));
if(lCard.getFaceValue() == VALUE_TEN) printw(" ");
else printw(" ");
}
}
}
/* printHandsCurses() - A function to display the current scores and hands for this game
* using curses.
*
* This function is used in promptPlayerCurses() to show the hands before asking them if
* they want to hit or stand. Note that it alsways clears the window before drawing.
*/
void BlackjackGame::printHandsCurses(bool pShowDealerScore) const
{
// Clear window
erase();
// Show dealer and player hands
attron(COLOR_PAIR(NORM_TEXT));
mvprintw(0, 0, "Player: %d\n", mPlayer.score());
move(1, 0); mPlayer.printCurses();
attron(COLOR_PAIR(NORM_TEXT));
if(pShowDealerScore)
{
mvprintw(0, 50, "Dealer: %d\n", mDealer.score());
}
else
{
mvprintw(0, 50, "Dealer: ??\n");
}
move(1, 50); mDealer.printCurses();
refresh();
}
/* getGameStat() - Examine the hands of both players and return the current state of
* the game using the eGameState enum.
*
* You must examine the state of the game by comparing the two hands (their scores and their
* number of cards) and return the appropriate constant from the eGameState enum. Assume
* that the game is over (i.e. the player and dealer have both either gone bust or decided
* to stand).
*/
eGameState BlackjackGame::getGameState() const
{
if(mDealer.hasBlackjack() && mPlayer.hasBlackjack())
{
return GAME_BLACKJACK_PUSH;
}
else if(mDealer.hasBlackjack())
{
return GAME_DEALER_BLACKJACK;
}
else if(mPlayer.hasBlackJack())
{
return GAME_PLAYER_BLACKJACK;
}
else if(mPlayer.score() > 21)
{
return GAME_PLAYER_BUST;
}
else if(mDealer.score() > 21)
{
return GAME_DEALER_BUST;
}
else if(mDealer.score() > mPlayer.score())
{
return GAME_DEALER_WIN;
}
else if(mDealer.score() < mPlayer.score())
{
return GAME_PLAYER_WIN;
}
else {
return GAME_PUSH;
}
}
}
主要
#include <cstdlib>
#include <iostream> // Standard input and output
#include <string>
using namespace std;
#include <curses.h>
#include "BlackjackGame.h"
// Three different types of text colors used with PDCurses
#define NORM_TEXT 1
#define WIN_TEXT 2
#define LOSE_TEXT 3
int main()
{
// Setup 'PDcurses'
initscr();
start_color();
// Define our colors text colors (foreground, background)
init_pair(NORM_TEXT, COLOR_WHITE, COLOR_BLACK);
init_pair(WIN_TEXT, COLOR_YELLOW, COLOR_BLACK);
init_pair(LOSE_TEXT, COLOR_RED, COLOR_BLACK);
// Define our card colors (these are declared in PrintableCard.h)
init_pair(BLACK_CARD, COLOR_BLACK, COLOR_WHITE);
init_pair(RED_CARD, COLOR_RED, COLOR_WHITE);
// Input from the user and a game object
char ch = '[=13=]';
BlackjackGame myGame;
// Output a 'fancy' welcome screen
myGame.printDeckCurses();
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(1, 13, "Welcome to Blackjack!");
mvprintw(5, 11, "Press any key to play ...");
refresh();
// Wait for input (the 'press any key to begin' thing)
ch = getch();
// Back to normal text to start the game
attron(COLOR_PAIR(NORM_TEXT));
do // Loop to play a new game until the user exits
{
// Restart and play a game (using curses)
myGame.newGame();
// Play a round of blackjack (most of the magic happens here!)
myGame.playGameCurses();
// Print the final status of the game
myGame.printHandsCurses(true);
// Print a game results message (use BOLD and the appropriate text color)
attron(A_BOLD);
switch(myGame.getGameState())
{
case GAME_BLACKJACK_PUSH:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "BLACKJACK TIE!!");
break;
case GAME_DEALER_BLACKJACK:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "Dealer Blackjack. You lose.");
break;
case GAME_PLAYER_BLACKJACK:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "BLACKJACK! You win!");
break;
case GAME_DEALER_BUST:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "Dealer Bust. You Win!");
break;
case GAME_PLAYER_BUST:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "BUST. You lose.");
break;
case GAME_DEALER_WIN:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "You lose.");
break;
case GAME_PLAYER_WIN:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "You Win!");
break;
case GAME_PUSH:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "It's a tie!");
break;
}
// Turn off bold and return to normal text color
attroff(A_BOLD);
attron(COLOR_PAIR(NORM_TEXT));
// Prompt user to play again
mvprintw(20, 0, "Play again (y/n): ");
refresh();
ch = getch();
} while(ch != 'n');
// Close out 'PDCurses' and pause before exiting
endwin();
system("pause");
return 0;
}
在这个程序中，我尝试创建游戏 BlackJack，大部分游戏都在其他文件中，但我没有收到其他文件中的错误。错误来自 Main 内部的代码。错误是
undefined reference to `BlackjackGame::blackjackGame()
undefined reference to `BlackjackGame::printDeckCurses()
undefined reference to `BlackjackGame::newGame()
undefined reference to `BlackjackGame::playGameCurses()
undefined reference to `BlackjackGame::printedHandsCurses()
undefined reference to `BlackjackGame::getGameState()
由于所有这些错误都来自 main 和 header 中的这些引用，这一定是我的问题，将两者联系起来。对吗？
这个问题告诉您，当您构建可执行文件或库时，您没有 link 在 BlackjackGame.o 目标文件中。
为了通过 linking 阶段，您必须将此文件中的 Makefile 修改为 link。
编辑：
查看您如何使用 Codeblocks 进行编译，检查这些 links（因为此错误消息在不同的编译器中意味着不同的事情）：
undefined reference to function code blocks
Code::Blocks 10.05 Undefined reference to function
根据 link 2
中的答案，您似乎需要将 BlackJackGame.cpp 添加到您的项目中
转到 Project/Add 文件将 BlackJackGame 源文件添加到您的项目，然后重新构建，这应该可以工作
在 Code::Blocks 中尝试编译我的代码时，我收到一堆未定义的引用错误。代码如下。
Header
#ifndef BLACKJACK_GAME
#define BLACKJACK_GAME
// A game of blackjack has a deck and two hands
#include "Deck.h"
#include "BlackjackHand.h"
// Different ways the game can end. The first states take precedence over
// over the latter states so check for the early ones first (like blackjack)!
// Note that a "natural 21" is when you are delt two cards totaling 21.
enum eGameState {
GAME_BLACKJACK_PUSH, // Both player and dealer have a natural 21
GAME_DEALER_BLACKJACK, // Dealer has a natural 21
GAME_PLAYER_BLACKJACK, // Player has a natural 21
GAME_DEALER_BUST, // The dealer has more than 21
GAME_PLAYER_BUST, // The player has more than 21
GAME_DEALER_WIN, // The dealer's score is higher than players
GAME_PLAYER_WIN, // The player's score is higher than dealers
GAME_PUSH // The scores are tied
};
class BlackjackGame
{
public:
BlackjackGame();
// Clear the players hands and shuffle the deck
void newGame();
// Play a single round of blackjack showing the output using
// the 'PDcurses' library (for color and card suits).
void playGameCurses();
// Display the deck on the screen (for debugging purposes)
void printDeckCurses();
// Print both players hands to the screen using 'PDCurses'
// If pShowDealerScore is true then the dealer's score is printed
// Otherwise, the dealer's score is shown as '??'
void printHandsCurses(bool pShowDealerScore = false) const;
// Determine the state of the game. Note that if you have not yet
// played a round since you constructed this object or called newGame()
// Then the state returned is not accurate.
eGameState getGameState() const;
private:
// A deck of cards for shufflying and dealing hands
Deck mDeck;
// The two hands for the player and the dealer
BlackjackHand mPlayer, mDealer;
// A helper function for prompting the player (internal use only)
char promptPlayerCurses();
// A helper function to quit the game (internal use only)
void quitGameCurses();
};
#endif
CPP
#include "BlackjackGame.h"
// The library used for our text based user interface
#include <curses.h>
// Normal text color for PDCurses (defined in main)
#define NORM_TEXT 1
// Default constructor (does nothing)
BlackjackGame::BlackjackGame() {}
/* newGame() - Clear the two hands so we are ready for a new game */
void BlackjackGame::newGame()
{
mDealer.clear();
mPlayer.clear();
}
/* playGameCurses() - Play a single round of poker with one human player and one
* dealer following standard Vegas rules. Uses PDCurses for input and output to
* the console.
*
* You must implement this method but you do not need to worry about curses. Call
* 'promptPlayerCurses() to show the hands and prompt the human player to hit, stand
* or quit. This method will return the key they pressed. You can also use
* quitGameCurses() to exit properly if the user chose to 'quit'.
*/
void BlackjackGame::playGameCurses()
{
// TODO: Shuffle the deck and deal the cards (make sure dealer's first card is hidden).
mDeck.shuffle();
mPlayer.takeCard(mDeck.dealCard());
mDealer.takeCard(mDeck.dealCard());
mDealer.hideCard();
mPlayer.takeCard(mDeck.dealCard());
mDealer.takeCard(mDeck.dealCard());
// TODO: Check for a 'natural 21' (blackjack) before playing
if ( mDealer.hasBlackjack() || mPlayer.hasBlackjack())
quitGameCurses();
// TODO: Allower human player to hit, stand and quit as needed (repeat until player is done)
int flag = 0;
while(flag!=1)
{
char input = promptPlayerCurses(); // This line is an example only, a placeholder
switch(input)
{
case 'h': mPlayer.takeCard(mDeck.dealCard());
break;
case 's': flag =1;
break;
case 'q': quitGameCurses();
break;
default: break;
}
}
// TODO: Play the 'dealer' hand according to vegas rules
mDealer.showCards();
while(vegasDealerWouldHit())
{
mDealer.takeCard(mDeck.dealCard());
}
}
/* promptPlayerCurses() - Show the hands and prompt the human player to hit, stand or quit.
* output: returns the single character entered by the player at the prompt.
* - 'h' means hit, 's' means stand
* - 'q' means you should immediatly quit (call 'quitGameCurses()')
*/
char BlackjackGame::promptPlayerCurses()
{
// Show the hands
printHandsCurses();
// Hit or stand?
attron(COLOR_PAIR(NORM_TEXT));
mvprintw(3, 0, "Hit, stand or Quit ('h', 's', 'q'): ");
refresh();
// Read and return a single character
return getch();
}
/* quitGameCurses() - End curses output and exit the program immediately */
void BlackjackGame::quitGameCurses()
{
// End curses output, then pause and exit
endwin();
system("pause");
exit(0);
}
/* printDeckCurses() - A handy function that displays the content of the game deck
* using curses.
*
* This can be handy for debugging your deck and making sure it is getting properly
* shuffled. It is presently used for the fancy opening screen.
*/
void BlackjackGame::printDeckCurses()
{
// Start at the upper left corner of the screen
move(0, 0);
// For all 52 cards
for(int i=1; i<=52; i++)
{
// Get the next card and print it
PrintableCard lCard = mDeck.dealCard();
lCard.printCurses();
// If we've output 13 cards then move down a row
if(i%13 == 0)
{
move(2*(i/13), 0);
}
else
{
// Switch back to normal text color and output ' ' characters
attron(COLOR_PAIR(NORM_TEXT));
if(lCard.getFaceValue() == VALUE_TEN) printw(" ");
else printw(" ");
}
}
}
/* printHandsCurses() - A function to display the current scores and hands for this game
* using curses.
*
* This function is used in promptPlayerCurses() to show the hands before asking them if
* they want to hit or stand. Note that it alsways clears the window before drawing.
*/
void BlackjackGame::printHandsCurses(bool pShowDealerScore) const
{
// Clear window
erase();
// Show dealer and player hands
attron(COLOR_PAIR(NORM_TEXT));
mvprintw(0, 0, "Player: %d\n", mPlayer.score());
move(1, 0); mPlayer.printCurses();
attron(COLOR_PAIR(NORM_TEXT));
if(pShowDealerScore)
{
mvprintw(0, 50, "Dealer: %d\n", mDealer.score());
}
else
{
mvprintw(0, 50, "Dealer: ??\n");
}
move(1, 50); mDealer.printCurses();
refresh();
}
/* getGameStat() - Examine the hands of both players and return the current state of
* the game using the eGameState enum.
*
* You must examine the state of the game by comparing the two hands (their scores and their
* number of cards) and return the appropriate constant from the eGameState enum. Assume
* that the game is over (i.e. the player and dealer have both either gone bust or decided
* to stand).
*/
eGameState BlackjackGame::getGameState() const
{
if(mDealer.hasBlackjack() && mPlayer.hasBlackjack())
{
return GAME_BLACKJACK_PUSH;
}
else if(mDealer.hasBlackjack())
{
return GAME_DEALER_BLACKJACK;
}
else if(mPlayer.hasBlackJack())
{
return GAME_PLAYER_BLACKJACK;
}
else if(mPlayer.score() > 21)
{
return GAME_PLAYER_BUST;
}
else if(mDealer.score() > 21)
{
return GAME_DEALER_BUST;
}
else if(mDealer.score() > mPlayer.score())
{
return GAME_DEALER_WIN;
}
else if(mDealer.score() < mPlayer.score())
{
return GAME_PLAYER_WIN;
}
else {
return GAME_PUSH;
}
}
}
主要
#include <cstdlib>
#include <iostream> // Standard input and output
#include <string>
using namespace std;
#include <curses.h>
#include "BlackjackGame.h"
// Three different types of text colors used with PDCurses
#define NORM_TEXT 1
#define WIN_TEXT 2
#define LOSE_TEXT 3
int main()
{
// Setup 'PDcurses'
initscr();
start_color();
// Define our colors text colors (foreground, background)
init_pair(NORM_TEXT, COLOR_WHITE, COLOR_BLACK);
init_pair(WIN_TEXT, COLOR_YELLOW, COLOR_BLACK);
init_pair(LOSE_TEXT, COLOR_RED, COLOR_BLACK);
// Define our card colors (these are declared in PrintableCard.h)
init_pair(BLACK_CARD, COLOR_BLACK, COLOR_WHITE);
init_pair(RED_CARD, COLOR_RED, COLOR_WHITE);
// Input from the user and a game object
char ch = '[=13=]';
BlackjackGame myGame;
// Output a 'fancy' welcome screen
myGame.printDeckCurses();
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(1, 13, "Welcome to Blackjack!");
mvprintw(5, 11, "Press any key to play ...");
refresh();
// Wait for input (the 'press any key to begin' thing)
ch = getch();
// Back to normal text to start the game
attron(COLOR_PAIR(NORM_TEXT));
do // Loop to play a new game until the user exits
{
// Restart and play a game (using curses)
myGame.newGame();
// Play a round of blackjack (most of the magic happens here!)
myGame.playGameCurses();
// Print the final status of the game
myGame.printHandsCurses(true);
// Print a game results message (use BOLD and the appropriate text color)
attron(A_BOLD);
switch(myGame.getGameState())
{
case GAME_BLACKJACK_PUSH:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "BLACKJACK TIE!!");
break;
case GAME_DEALER_BLACKJACK:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "Dealer Blackjack. You lose.");
break;
case GAME_PLAYER_BLACKJACK:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "BLACKJACK! You win!");
break;
case GAME_DEALER_BUST:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "Dealer Bust. You Win!");
break;
case GAME_PLAYER_BUST:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "BUST. You lose.");
break;
case GAME_DEALER_WIN:
attron(COLOR_PAIR(LOSE_TEXT));
mvprintw(10, 25, "You lose.");
break;
case GAME_PLAYER_WIN:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "You Win!");
break;
case GAME_PUSH:
attron(COLOR_PAIR(WIN_TEXT));
mvprintw(10, 25, "It's a tie!");
break;
}
// Turn off bold and return to normal text color
attroff(A_BOLD);
attron(COLOR_PAIR(NORM_TEXT));
// Prompt user to play again
mvprintw(20, 0, "Play again (y/n): ");
refresh();
ch = getch();
} while(ch != 'n');
// Close out 'PDCurses' and pause before exiting
endwin();
system("pause");
return 0;
}
在这个程序中，我尝试创建游戏 BlackJack，大部分游戏都在其他文件中，但我没有收到其他文件中的错误。错误来自 Main 内部的代码。错误是
undefined reference to `BlackjackGame::blackjackGame()
undefined reference to `BlackjackGame::printDeckCurses()
undefined reference to `BlackjackGame::newGame()
undefined reference to `BlackjackGame::playGameCurses()
undefined reference to `BlackjackGame::printedHandsCurses()
undefined reference to `BlackjackGame::getGameState()
由于所有这些错误都来自 main 和 header 中的这些引用，这一定是我的问题，将两者联系起来。对吗？
这个问题告诉您，当您构建可执行文件或库时，您没有 link 在 BlackjackGame.o 目标文件中。
为了通过 linking 阶段，您必须将此文件中的 Makefile 修改为 link。
编辑： 查看您如何使用 Codeblocks 进行编译，检查这些 links（因为此错误消息在不同的编译器中意味着不同的事情）：
undefined reference to function code blocks
Code::Blocks 10.05 Undefined reference to function
根据 link 2
中的答案，您似乎需要将 BlackJackGame.cpp 添加到您的项目中转到 Project/Add 文件将 BlackJackGame 源文件添加到您的项目，然后重新构建，这应该可以工作