While Loop is Crashing Program

[Wander]

I am making a program to generate random dungeons. So far I have it where the program can fill the map with solid earth and then carve out a room at a random position on the map as the starting point.

This function:

void buildDung(int low, int range)
    {
        /// Finds a suitable area to build a feature ///
        int xCoord = randGen(2,67);
        int yCoord = randGen(2,42);
        while(map[xCoord][yCoord] != " ")
        {
            xCoord = randGen(2,67);
            yCoord = randGen(2,42);
        }
        choose:

        goto choose;
    }

Is giving me a good amount of trouble. This function is supposed to the search spots on the map until it finds a spot where there is no earth. It seems like it would work, but it keeps crashing my program... I have no clue as to why. Any help would be great!

[filipe]

While I can't tell what randGen() does and what map[][] really is, you can't expect control to ever get past line 13. This:

label:
goto label;

is the same as saying:

while(true) { };

It's just a never ending loop, though I don't see how it could crash the program at all.

Incidentally, don't use the goto statement. There's always a better, structured way to deal with program flow.

[Wander]

I took the goto loop out and it still crashes.

randGen() generates a random number.
map[][] is a multidimensional array that holds the values for each square on the map.

[Wander]

Okay! I found out what is making it crash, but I don't know why.

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***************____*****
***************____*****
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Suppose that this is the dungeon that my program made. The earth is made of * and the room is just spaces. If I have the while loop search for what character makes up the room (whether is be spaces, &, etc) it crashes. If the while loop search for something on the walls it won't. I don't understand.

[filipe]

randGen() generates a random number.

That I could tell, but you'd need to post the function for us to see what's going on. Is it guaranteed to return only values in the range of map[][]? Is map[][] an array of strings? Can you post its declaration?

[Wander]

string map[x][y];

int randGen(int low, int range)
    {
        /// Generates random numbers in the range that is specified ///
        return low+int(range*rand()/(RAND_MAX + 1.0));
    }

void firstRoom()
    {
        /// Carves out the first room of the dungeon ///
        int down = randGen(10,21);
        int left = randGen(10,21);
        int width = randGen(3,6);
        int length = randGen(3,6);
        int a = x-down;
        int aa = a+length;
        int b = y-left;
        int bb = b+width;
        for (int xCoord = a; xCoord < aa; xCoord++) {
            for (int yCoord = b; yCoord < bb; yCoord++) {
                map[xCoord][yCoord] = " ";
            }
        }
    }

[Wander]

Do you think that the program just can't handle jumping around the map so quickly with the while loop and random numbers?

[rocketboy9000]

Assuming that the definition of map is something like string **map; or string map[70][45];
make sure that the parts of the array exist. exactly how big is map?

[Wander]

45 by 70

map[45][70];

[Wander]

OH MY GOD YES!! I FIXED IT!! Thank you for asking about the dimensions! You got me thinking and now I fixed it. I had the random numbers generating opposite what they should be.