Trouble using function pointers as parameters.

[Thomas Nelson]

I'm trying to write a function that uses function pointers. Here's my
errors:
Board.cc:111: error: expected ',' or '...' before 'p1'
Board.cc:111: error: prototype for 'int Board:lay_game(int (*)(const
Board&))' does not match any in class 'Board'
Board.h:18: error: candidate is: int Board:lay_game(int (*)(const
Board&), int (*)(const Board&), bool)


Here's Board.cc:111:

int Board:lay_game(int(const Board &) p1, int(const Board &) p2,
bool silent=false)

And here's Board.h:18:

int play_game(int(const Board &), int(const Board &), bool
silent);

What have I done wrong? I wanted to use a typedef to simplify this,
but Board has to be declared to use it in a typedef, and I want to use
the typedef in my Board declaration. Any help would be great.

Thanks,
Tom

 

[Victor Bazarov]

I'm trying to write a function that uses function pointers. Here's my
errors:
Board.cc:111: error: expected ',' or '...' before 'p1'
Board.cc:111: error: prototype for 'int Board:lay_game(int (*)(const
Board&))' does not match any in class 'Board'
Board.h:18: error: candidate is: int Board:lay_game(int (*)(const
Board&), int (*)(const Board&), bool)


Here's Board.cc:111:

int Board:lay_game(int(const Board &) p1, int(const Board &) p2,
bool silent=false)

And here's Board.h:18:

int play_game(int(const Board &), int(const Board &), bool
silent);

What have I done wrong? I wanted to use a typedef to simplify this,
but Board has to be declared to use it in a typedef, and I want to use
the typedef in my Board declaration. Any help would be great.

Read the FAQ 5.8. That's for the next time. For now, however, try
changing it to

/* in header */
int play_game(int (*)(const Board&), int (*)(const Board&),
bool = false);
/* in TU */
int play_game(int (*p1)(const Board&), int (*p2)(const Board&),
bool silent /* = false */)
{
return 42;
}

V

 

[Thomas Nelson]

Read the FAQ 5.8. That's for the next time. For now, however, try
changing it to

/* in header */
int play_game(int (*)(const Board&), int (*)(const Board&),
bool = false);
/* in TU */
int play_game(int (*p1)(const Board&), int (*p2)(const Board&),
bool silent /* = false */)
{
return 42;
}

V

Thanks, this fixed my problem. Next time I will post more descriptive
code.

Tom

 

[Jonas]

I'm trying to write a function that uses function pointers. Here's my
errors:
Board.cc:111: error: expected ',' or '...' before 'p1'
Board.cc:111: error: prototype for 'int Board:lay_game(int (*)(const
Board&))' does not match any in class 'Board'
Board.h:18: error: candidate is: int Board:lay_game(int (*)(const
Board&), int (*)(const Board&), bool)


Here's Board.cc:111:

int Board:lay_game(int(const Board &) p1, int(const Board &) p2,
bool silent=false)

And here's Board.h:18:

int play_game(int(const Board &), int(const Board &), bool
silent);

What have I done wrong? I wanted to use a typedef to simplify this,
but Board has to be declared to use it in a typedef, and I want to use
the typedef in my Board declaration. Any help would be great.

Like so:

int Board:lay_game(int (*p1)(const Board &), int (*p2)(const Board &),
bool silent=false);

Or, using a typedef:

class Board {
typedef int func(const Board & board);
int play_game(func * p1, func * p2, bool silent=false);
};

Alternatively,

class Board;
typedef int func(const Board & board);

class Board {
int play_game(func * p1, func * p2, bool silent=false);
};