struct access error

Code:

#include <curses.h>

int s_palettep;
int s_usflag;
int s_cposr;
int s_cposc;

struct x_mttype   {   struct   {   unsigned int type    : 5;
                                   unsigned int obs     : 1;
                                   unsigned int mystery : 1;
                                   unsigned int locale  : 1;
                                   unsigned int link    : 1;
                                   unsigned int         : 7;
                               } tile;
                      struct   {
                                   unsigned int tchar   : 8;
                                   unsigned int palette : 5;
                                   unsigned int bright  : 1;
                                   unsigned int         : 2;
                               } tiledat;
                  };

struct x_mttype s_maptemp[19][79];

void clearmap();
void edit();
void ivar();

int main()
{
  ivar();
  initscr();
  keypad ( stdscr, TRUE );

  edit();

  endwin();
  return 0;
}

That is main.cpp

Code:

extern struct x_mttype s_maptemp;

void clearmap()
{
  for (int a = 0; a < 20; ++a)
  {
    for (int b = 0; b < 80; ++b)
    {
       s_maptemp[a][b].tile.type=0;
    }
  }
}

That is clearmap.cpp

My problem is that I get this error, when I compile and run the program:

Code:

9 clearmap.cpp
 no match for `x_mttype &[int]'

Not certain since I'm not too familiar with the extern command, but could it be because you declare your map as an array in main but only as a single instance in clearmap.cpp?

i still get errors when i add the brackets

Heres an idea instead of having a global why not pass it to the function?

You can't really do that in roguelikes. Would not I have to send a pointer to the object, to the function, though?

Explain how passing works, if thou dost please.

just a guess

extern struct x_mttype s_maptemp[][];
or
extern struct x_mttype s_maptemp[][79];
or
extern struct x_mttype s_maptemp[19][79];

You would pass the struct as you would any other array.

Code:

#include <iostream>
using namespace std;

struct map
{    
    int x;
    int y;
};

void setXY(map setMap[],const int size)
{
    int i = 0;
    while(i < size)
    {
        setMap[i].x = 3;
        setMap[i].y = 6;
        i++;
    }
}

int main()
{
    int i = 0;
    map mainMap[5];
    setXY(mainMap,5);
    while(i < 5)
    {
        cout<<mainMap[i].x<<endl;
        cout<<mainMap[i].y<<endl;
        i++;
    }
    cin.get();
    return 0;
}

Look, I don't think you can access a variable in main from a function called in main; you're gonna have to explain that to me, it's just not makin' any sense.

Code:

struct x_mttype   {   struct   {

Put this in a header file, and include it in all the source files which refer to it.

> extern struct x_mttype s_maptemp;
Specify some dimensions - like the ones you used when you declared it.

> for (int a = 0; a < 20; ++a)
Should be < 19, since that's all you specified.
You're stepping off the ends big-time here.
A better idea would be to have some constants for the dimensions, rather than littering the code with all these magic numbers.

Look, I don't think you can access a variable in main from a function called in main;

Of course not. But you can access a pointer or reference to the variable, if it's passed as a parameter (argument) to the function. The reverse is not true (main cannot access the variables in a function it calls) because any variables declared within the function, with the exception of static variables, will go out of scope when the function ends.

Functions:
http://www.cprogramming.com/tutorial/lesson4.html

Pointers:
http://www.cprogramming.com/tutorial/lesson6.html