rand() - simulation program - seed

[jdwright]

I had a previous post about this same program, but now I am at a new topic, so I created a new thread. Below, I am using

cout << jumps << endl;
cout << loss << endl;

to view the resulting numbers, and disregarding the displayInfo right now. The problem is that every time the loop

 while (simRun < 501)
    {
        while (runs != 1)
        {
            jumpFleas (grid1, grid2, loss);
            jumps += 1;
            runs = checkSquares(grid2);
            resetGrid(grid1, grid2);
            zeroOut(grid2);
        }
        cout << jumps << endl;
        cout << loss << endl;
        simRun++;
    }

runs through, I get the exact same number of jumps and loss. I need these to be different, because this is a simulation program. I've tried seeding to no avail. Looking for some thoughts on how to fix this.

The full program:

#include <iostream>
#include <cstdlib>
#include <time.h>
using namespace std;

int checkSquares(int [][22]);
void jumpFleas(int [][22], int [][22], int &);
void resetGrid(int [][22], int [][22]);
void zeroOut(int [][22]);
void initialize(int [][22]);
void getTotals(int, int, int, int);
void getMinMax(int, int, int);
void displayInfo(int, int, int, int);

int main()
{
    
    int simRun = 0;
    int min = 10000, max = 0, jumps = 0, loss = 0, runs = 0;
    int TOTALJ = 0, TOTALL = 0;
    int grid1[22][22];
    int grid2[22][22];
    initialize(grid1);
    zeroOut(grid2);
    
  
    
    while (simRun < 501)
    {
        while (runs != 1)
        {
            jumpFleas (grid1, grid2, loss);
            jumps += 1;
            runs = checkSquares(grid2);
            resetGrid(grid1, grid2);
            zeroOut(grid2);
        }
        cout << jumps << endl;
        cout << loss << endl;
        simRun++;
    }
    
    getTotals(jumps, loss, TOTALJ, TOTALL);
    getMinMax(jumps, min, max);

    displayInfo(TOTALJ, TOTALL, min, max);


    return 0;
}

void jumpFleas(int grid1[][22], int grid2[][22], int &loss)
{
    int r,c, move;
    
    for (r=1; r<22; r++)
    {
        for (c=1; c<22; c++)
        {
            
            move = (rand() % 100) + 1;
            
            if (move>0 && move<16)
            {
                grid2[r][c] += grid1[r][c];
            }
            if (move>15 && move<31)
            {
                grid2[r+1][c] += grid1 [r][c];
                if ((r+1) == 22)
                {
                    loss += 1;
                }
            }
            if (move>30 && move<36)
            {
                grid2[r+1][c+1] += grid1[r][c];
                if (((r+1) == 22) || ((c+1) == 22))
                {
                    loss += 1;
                }
            }
            if (move>35 && move<56)
            {
                grid2[r][c+1] += grid1 [r][c];
                if ((c+1) == 22)
                {
                    loss += 1;
                }
            }
            if (move>55 && move<61)
            {
                grid2[r-1][c+1] += grid1 [r][c];
                if (((r-1) == 0) || ((c+1) == 22))
                {
                    loss += 1;
                }
            }
            if (move>60 && move<76)
            {
                grid2[r-1][c] += grid1[r][c];
                if ((r-1) == 0)
                {
                    loss += 1;
                }
            }
            if (move>75 && move<81)
            {
                grid2[r-1][c-1] += grid1[r][c];
                if (((r-1) == 0) || ((c-1) == 0))
                {
                    loss += 1;
                }
            }
            if (move>80 && move<96)
            {
                grid2[r][c-1] += grid1[r][c];
                if ((c-1) == 0)
                {
                    loss += 1;
                }
            }
            if (move>95 && move<101)
            {
                grid2[r+1][c-1] += grid1[r][c];
                if (((r+1) == 22) || ((c-1) == 0))
                {
                    loss += 1;
                }
            }
            move = 0;
        }
    }
}

int checkSquares(int grid2[][22])
{
    int r,c, runs;
    int count = 0;
    
    for (r=1; r<22; r++)
    {
        for (c=1; c<22; c++)
        {
            if (grid2[r][c] == 0)
            {
                count++;
            }
        }
    }
    
    if (count > 299)
    {
        runs = 1;
    }
    else
    {
        runs = 0;
    }
    //cout << runs;
    return runs;
}

void getTotals(int jumps, int loss, int totalJ, int totalL)
{
    totalJ += jumps;
    totalL += loss;
}

void getMinMax (int jumps, int min, int max)
{
    if (jumps < min)
    {
        min = jumps;
    }
    if (jumps > max)
    {
        max = jumps;
    }
}

void resetGrid(int grid1[][22], int grid2[][22])
{
    int r,c;
    for (r=1; r<22; r++)
    {
        for (c=1; c<22; c++)
        {
            grid1[r][c] = grid2[r][c];
        }
    }
}

void zeroOut(int grid2[][22])
{
    int r,c;
    for (r=1; r<22; r++)
    {
        for (c=1; c<22; c++)
        {
            grid2[r][c] = 0;
        }
    }
}

void initialize(int grid1[][22])
{
    int r,c;
    for (r=1; r<22; r++)
    {
        for (c=1; c<22; c++)
        {
            grid1[r][c] = 1;
        }
    }
}

void displayInfo(int TOTALJ, int TOTALL, int min, int max)
{
    int avgJ, clearTime, avgL, maxTime, minTime;
    avgJ = TOTALJ / 500;
    clearTime = (TOTALJ * 8) / 5;
    maxTime = (max * 8) / 5;
    minTime = (min * 8) / 5;
    avgL = TOTALL / 500;
    
    cout << "The average number of jumps before fire: " << avgJ << endl;
    cout << "The amount of time needed to clear the area: " << clearTime << endl;
    cout << "The shortest time: " << minTime << endl;
    cout << "The longest time: " << maxTime << endl;
    cout << "The average number of fleas lost before fire: " << avgL << endl;
}

[Zhuge]

I don't see you seeding the random number generator anywhere. Add a call to srand() at the start of main().
http://www.cplusplus.com/reference/cstdlib/srand/

[jdwright]

Yeah I did that. It didn't work so I took it out. It still did the same numbers every time just different ones than before.

[Zhuge]

Are you giving srand() the same seed every time?

[jdwright]

I tried using the time(0) and time(NULL) ones

[xismn]

You can just wrap the rand functionality into a function.

int random(int min, int max) {
	static bool random = false;
	if(!random) {
		random = true;
		srand(time(0));
	}
	return min + (rand%(max-min+1));
}

[ne555]

> It didn't work so I took it out
Don't post code which is different from your own but does not reproduce the problem ( or has other problems )

Not using `srand()' is different than using `srand()' incorrectly


As I said in http://www.cplusplus.com/forum/beginner/124362/#msg676241 your loop in line 30 executes only in the first iteration.

However, you should seed the rng, otherwise the next time you run your program you'll get the same results.

[jdwright]

Well I added runs = 0, jumps = 0, and loss = 0 right about my

while (runs != 1)

loop. My output goes like:

4
84
1
27
1
23
1
20
1
17

and so on. So jumps is 4 for the first run, but only one for all the rest of them. I'm very confused about why.

[jdwright]

I meant right above*

[ne555]

You are accessing out of bounds in the `jumpFleas()' function
by instance grid2[r+1][c+1] += grid1[r][c];

> My output goes like:
¿what's supposed to be?


void getTotals(int, int, int, int);
your function has no effect

Also, I think that you need to `initialze()' `grid1'