Thread: Memory Allocation

I don't know what you're trying to do, but it doesn't sound like a good idea at all.

Actually, its a very good idea. I'm writing a MUD game and when a player sends a command to the game server, I compare the command sent to the existing function names that I give it, ifit compares currectley then it calls that function. Sorta like a dynamic function call.

You are a confused man

Look, you can technically cast the char array into a function pointer, but this will not do anything (but possiblly crash your computer!)

Having said that...enjoy.

Code:

struct command_type
{
 void (*function)(char *, char *);  //function
};


int main(){
struct command_type cmd;
char *com = "walk_north";
char *crash, *me;
cmd.function = (void(*)(char*, char*))com;
cmd.function(crash, me);

return 0;
}

Perhaps a

Code:

 
std::map<string , void(*)(char*,char*)>

is what you want?
Read some STL tutorial.

Actually, its a very good idea

Ok, look. what you're referring to is a function table:

void North(){}
void South(){}

char *cmd[] = { { "north" }, {"south"} };

void (*fp[2])(void) = { {North}, {South} };


//...


if((strcmp(cmd[i], input))==0)
fp[i]();

Here's an elabortion of Sang- drax's suggestion....You need a decent stl aware compiler....Codewarrior.....Mingw (IE with devc++)...it will choke to death on VC++6

Code:

#include <iostream>
#include <map>
#include <string>

void Func1(void);
void Func2(void);
void Func3(void);
typedef void(*funp)(void);//this is a nead typedef for our func pointer



int main(){

	typedef std::map<std::string,funp> MYMAP;//another typedef to save typing
	MYMAP MyMap;//We create a map object

	//Now we add each func name as a string and a pointer to its function
	MyMap.insert(MYMAP::value_type(std::string("Func1"),Func1));
	MyMap.insert(MYMAP::value_type(std::string("Func2"),Func2));
	MyMap.insert(MYMAP::value_type(std::string("Func3"),Func3));
	
	std::string str;
	
	while(1){
		
		std::cout << "Enter Function Name" << std::endl;
		std::cout << "Func1, Func2 or Func3..or exit to quit" << std::endl;
		std::getline(std::cin,str);
		std::cout << std::endl;
		if(!str.compare("exit"))break;
		if(MyMap.find(str) == MyMap.end()){//If not in map..try again!
			std::cout << "Invalid choice" << std::endl;
			continue;
		}		
		(MyMap[str])();//Get the function ptr and call it
		continue;
	}
	
	std::cout << "That's all folks!!!" << std::endl;

}

void Func1(void){
	std::cout << "Congrats!!..You called Func1" << std::endl << std::endl;
}
void Func2(void){
	std::cout << "Congrats!!..You called Func2" << std::endl << std::endl;
}
void Func3(void){
	std::cout << "Congrats!!..You called Func3" << std::endl << std::endl;
}

Well things seem to be a little... out of proportion, you could say. Let me elaborate on the code. Please note I had a previous working version that someone wrote for me, but I changed my command system in the MUD game, so Its been re-written.

Code:

struct command_type
{
	void	(*funp)(CHAR_DATA *ch, char *args);
};

....

const struct command_type player_commands[] = {
	{ c_bug	},

	{ c_editcmd },

	{ c_halt	},

	{ c_idea	},

	{ c_logview },

	{ c_makecmd },

	{ c_motd	},

	{ c_password },

	{ c_quit	},

	{ c_reset_char },

	{ c_save	},

	{ c_savecmds },

	{ c_say	},

	{ c_show_flags	},

	{ c_toggle_flag },

	{ c_typo	},

	{ c_who	},

	{ NULL	}
};

void command_interp(CHAR_DATA *ch, char *input)
{
	char *command;
	char *args;
	COMMAND_DATA *cmd;
	int i;
	bool bad_c=FALSE;
	// Note: GNU claims strtok is very bad, the security concerned could
	// change this to something else.
	command = strtok(input, " ");
	args = strtok(NULL, "");

	if((input[0]==' ') || (input==NULL))
		bad_c=TRUE;
/*
	for (i=0; player_commands[i].name[0] != '\0'; i++) {
		if(bad_c==TRUE)
			break;
		if (!strcmpi(command, player_commands[i].name)) {
			((player_commands[i].funp))(ch, args);
			return;
		}
	} */

	for(cmd=first_command;cmd!=NULL;cmd=cmd->next){
		if(bad_c==TRUE)
			break;
		if(!strcmpi(command, cmd->name)) {
				((cmd->function))(ch, args);
				return;
		}
	}

	bad_command(ch);
}

Well, perhaps that will clear up exactley what I'm trying to do? Oh, and one more thing. I'm using MSVC++ 6.0 IDE to edit the code, but its being written to run under linux, or *unix environments. I'm using cygwin to compile under windows.

Thanks again.