Question

Guys I’m getting this really weird fault with my program when I run it. This is the important code:

variables (edit):

const short int maxX = 100;
const short int maxZ = 100;
const short int lakeChance = 0.9;

addLake function (edit):

void addLake(Sect sector[][maxZ], int x, int z){    
    sector[x][z].setMaterial(1);
}

main source (edit):

//Generating land mass
for (int x = 0; x < maxX; x++){
    for (int z = 0; z < maxZ; z++){
        //Default material
        sector[x][z].setMaterial(0);

        //Add lake/sea source
        int r = rand();
        float r1 = (r % 1000);
        float r2 = r1 / 1000;

        if (r2 <= lakeChance) addLake(sector, x, z);
    }
}

The fault is, that whatever I change the ‘lakeChance’ value to, the result seems to be exactly the same. As in the addLake function seems to be called about 3 to 6 times every launch despite me changing the value of lakeChance higher (i.e.: 0.5, 0.7, 0.9). The function is only called all the time when I change the value of ‘lakeChance’ to 1. The random number generator works fine btw so the result are somewhat varying every time.

Answer 1

I see nothing obviously wrong per se. So I tried the following bit of code:

int test(float chance)
{
    int call = 0;

    for(int i = 0; i != 100000; i++)
    {
        int r = rand();

        float r1 = (r % 1000);

        float r2 = r1 / 1000;

        if(r2 <= chance)
            call++;
    }

    cout << "Chance is " << chance << ": " << call << " invocations or "
         << ((100.0 * call) / 100000.0) << "% of the time!" << endl;

    return call;    
}

Predictably, I got these results:

Chance is 0.1: 10216 invocations or 10.216% of the time!
Chance is 0.2: 20232 invocations or 20.232% of the time!
Chance is 0.3: 30357 invocations or 30.357% of the time!
Chance is 0.4: 40226 invocations or 40.226% of the time!
Chance is 0.6: 60539 invocations or 60.539% of the time!
Chance is 0.7: 70539 invocations or 70.539% of the time!
Chance is 0.8: 80522 invocations or 80.522% of the time!
Chance is 0.9: 90336 invocations or 90.336% of the time!
Chance is 1: 100000 invocations or 100% of the time!

How many lakes are you trying to add?