Adventure for learning basics and more in c++ (Total noob). Now i made a Playground Array for all the fields to visit, but when it comes to the rand() function in a for loop it repeats the Nummber so it's not random generated. Some ideads to fix this issue? Note that iam not very into the rand func.
Thanks in advance!
Here is my code
#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
//**SETTINGS**
//Häufigkeit von field_type
#define VILLAGE 5
#define TOWN 2
int main()
{
//** THE PLAYGROUND **
struct field {
bool status;
string field_type;
};
int x = 5;
int y = 5;
field playground[5][5];
//Playground Typen definition
int village_counter = 0;
int town_counter = 0;
int x2 = 0;
int y2 = 0;
for (int counter = 0; counter < x * y; counter++) {
int Nummer;
srand(time(NULL));
Nummer = rand() % 4 + 1; // generates always the same number!
switch (Nummer) {
case 1:
village_counter++;
if (VILLAGE >= village_counter) {
playground[x2][y2].field_type = "VILLAGE";
}
else {
goto a_switch;
}
break;
case 2:
town_counter++;
if (TOWN >= town_counter) {
playground[x2][y2].field_type = "TOWN";
}
else {
goto b_switch;
}
break;
case 3:
a_switch:
playground[x2][y2].field_type = "GRASSLAND";
break;
case 4:
b_switch:
playground[x2][y2].field_type = "FOREST";
break;
}
x2++;
if (x2 == x) {
x2 = 0;
y2++;
}
}
//For test usage of all Field's
x2 = 0;
y2 = 0;
for (int counter = 0; counter < x * y; counter++) {
cout << counter << ": Field_TYPE = " << playground[x2][y2].field_type << endl;
x2++;
if (x2 == x) {
x2 = 0;
y2++;
}
}
}
time requests the current time in seconds as an integer. if your program takes less than a second to execute, then you will "seed" the random number generator with the same value every time. pseudo random number generators (i.e. your rand() call) return a deterministic series of values based on this state you seeded.
as #Scheff said, you're much better off just seeding once (probably at the beginning of the program) and then just calling rand() when you need it. note that srand and rand are old historical artifacts from C, and you're much better off using more modern generators that come with recent C++ compilers
see the docs on c++ random number generators for more information
Hello I am attempting to write a program and I seem to be stick. This program is in the end supposed to display two variants of a single 10 by 10 mine sweeper board. One of which where if there is a mine in that location it displays an asterisk(*) and if there is no mine it displays a period. The second variant also needs to display an asterisk where the mines are located on the board. But instead of a period it has to display the number of mines located 1 space away in any direction. I can't seem to think of how to easily write a program that will add up each of the mines located around each point. I also can't figure out why my program asks the initial question twice even if it meets the criteria for stopping the loop the first time around.
/*
Program: minesweeper(sort of)
The intention of this program is to display essentially two mine sweeper game boards one of which displays a *
where all of the mines would be located and a . where no mines are located. Then the second display
should display a * where all of the mines are and then display a number based on how many mines surround that space.
*/
#include <iostream>
#include <time.h>
#include <math.h>
using namespace std;
double get_probability();
int plant_mines(bool mineCells[10][10], double prob);
int print(bool mineCells[10][10]);
int count_mines(bool mineCells[10][10], int mineCounters[10][10]);
int main()
{
//used to hold true if there is a mine located at said location or false if there is no mine
bool mineCells[10][10];
//used to hold a value of -5 if the corrosponding value on mineCells is true and if the corrosponding value on
//minecells is false it should add up and hold the value of how many mines are surroudning it.
int mineCounters[10][10];
get_probability();
double prob = get_probability();
plant_mines(mineCells, prob);
print(mineCells);
int stop;
cin >> stop;
return 0;
}
//asks the user for a number between 0 and 1 to use as the probability of mines apearing laster on.
double get_probability()
{
double prob;
bool repeat;
do
{
cout << "Please enter a number between 0 and 1: ";
cin >> prob;
//should execute once asking the user for a input between 0 and 1 and if the input is not between those two it shoud
//then continue to repeat untill the permaiters set in the question are met.
if (prob >= 0 && prob <= 1)
{
break;
}
else
{
repeat = true;
}
}while (repeat = true);
return prob;
}
//takes the probability given by the user and then uses it to generate that percentage of mines on the field
int plant_mines(bool mineCells[10][10], double prob)
{
srand((unsigned int)time(NULL));
for (int count = 0; count < 10; count++)
{
for (int counter = 0; counter < 10; counter++)
{
//generates a random number between 0 and 1 and sets it equal to the variable random
double random = static_cast<double>(rand()) / RAND_MAX;
//is the variable random is less than or equal to the probability then the array is set to true meaning
//there is a mine located at that position
if (random <= prob)
{
mineCells[count][counter] = true;
}
//iff the random number is greater than the user input than there is no mine located at said position
else
{
mineCells[count][counter] = false;
}
}
}
return mineCells[10][10];
}
//Should count up the mines surronding the location to be output later on
//(the mines surrounding the location do include all mines 1 space diagonal, vertical and horizontal from said location)
int count_mines(bool mineCells[10][10], int mineCounters[10][10])
{
for (int count = 0; count < 10; count++)
{
for (int counter = 0; counter < 10; counter++)
{
if (mineCells[count][counter] == 1)
{
mineCounters[count][counter] = 0;
}
else
{
}
}
cout << endl;
}
return 0;
}
//displays a * where ever a mine is locate and a . where ever a mine is not located
int print(bool mineCells[10][10])
{
for (int count = 0; count < 10; count++)
{
for (int counter = 0; counter < 10; counter++)
{
if (mineCells[count][counter] == 1)
{
cout << "*";
}
else
{
cout << ".";
}
}
cout << endl;
}
return 0;
}
My Basic Algorithm:
Ask for input money amount; Rolls two 6-sided dice; if they add up to 7, add 4 to money amount; else, subtract 1 from money amount; loop until moneyamount<0; loop game user says n when prompted to play again.
/*
*File: hw3
*Author: Nathaniel Goodhue
*
*Created on: 9/15/15
*Description: Game of lucky sevens
*
*/
#include <iostream>
#include <cstdlib>
#include <cmath>
using namespace std;
int main()
{
srand (time(NULL));
double moneyAmount;
int winValue = 7;
int numRolls = 0;
char playAgain = 'y';
while(playAgain == 'y')
{
cout<<"Enter the amount of money you are playing with: $";
cin>>moneyAmount;
while(moneyAmount>0)
{
int roll1= (rand()%6)+1;
int roll2 = (rand()%6)+1;
if(roll1+roll2 == winValue)
{
moneyAmount+=4;
numRolls++;
}
else
{
moneyAmount-=1;
numRolls++;
}
}
cout<<"It took "<<numRolls<<" roll(s) to lose all of your money"<<endl;
// cout<<"Your maximum amount of money was $" <<maxAmount<<" after "<<maxRolls<<" roll(s)"<<endl;
cout<<"Play again? y/n"<<endl;
cin>>playAgain;
if(playAgain == 'y')
{
cout<<"Enter the amount of money you are playing with: $";
cin>>moneyAmount;
numRolls = 0;
}
else
{
break;
}
}
return 0;
}
Above is my current code. It works as intended. What I am stuck on is that I need to be able to implement this line of code right after money drops below 0:
cout<<"Your maximum amount of money was $" <<maxAmount<<" after "<<maxRolls<<" roll(s)"<<endl;
I need to find out when there was the most money and after how many rolls that it appeared. The maxAmount variable would be the max amount of money achieved, and the maxRolls variable would be the number of rolls when maxAmount was reached.
This is pretty simple to add to your code. What you can do is check if the amount of money they have is greater than the max amount of money. If it is then set max to current and record the number of turns it took to get that value.
int maxAmount = moneyAmount, maxRolls = 0;
while(moneyAmount > 0)
{
int roll1 = (rand() % 6) + 1;
int roll2 = (rand() % 6) + 1;
numRolls++;
if(roll1 + roll2 == winValue)
moneyAmount += 4;
else
moneyAmount -= 1;
if (moneyAmount > maxAmount)
{
// the current amount of money is greater than the max so set max to current and get the number of rolls
maxAmount = moneyAmount;
maxRolls = numRolls;
}
}
I have an assignment where I need to calculate the probability that two people share the same birthday for a given room size (in my case 50) over many trials (5000). I have to assign the birthdays randomly to the number of people in the room. The difference is I need to use a Boolean function to check the if the Birthdays are the same. I cannot figure why my outputs are off, but I believe it has something to do with two of my loops.
>
#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
bool SameBirthday(int birthdays[], int numpeople);
const int MAX_PEOPLE = 50;
const double NUM_TRIALS = 5000.0;
const int DAYS_IN_YEAR = 365;
int main(void)
{
int numMatches = 0;
int people = 2;
int trial = 0;
int numpeople = 0;
int i = 0;
int birthdays[MAX_PEOPLE];
bool Match;
double Probability = 0;
srand(time(0));
for (people = 2; people <= MAX_PEOPLE; people++)
{
numMatches = 0;
for (trial = 0; trial < NUM_TRIALS; trial++)
{
for (i = 0; i < people; i++)
{
birthdays[i] = (rand() % 365 + 1);
numpeople = i;
}
if ((SameBirthday(birthdays, numpeople) == true))
{
numMatches++;
}
}
Probability = (numMatches / NUM_TRIALS);
cout << "For " << people << ", the probability of two birthdays is about " << Probability << endl;
}
}
bool SameBirthday(int birthdays[], int numpeople)
{
bool match = false;
int numberofmatches = 0;
//Use this function to attempt to search the giving array birthdays and count up number of times
//at least two people have matching birthdays for any given 1 trial
for (int SpaceOne = 0; SpaceOne < numpeople; SpaceOne++)
{
for (int SpaceTwo = SpaceOne + 1; SpaceTwo < numpeople; SpaceTwo++)
{
if (birthdays[SpaceTwo] == birthdays[SpaceOne])
{
return true;
}
}
}
return false;
}
I know that the code has errors in certain spots that was because I started trying different things, but any help would be appreciated.
EDIT- My only issue now is that for my output I have a zero for the probability of 2 people in the room have a birthday, which is not right. It seems like my outputs are like a person off, the probability of 2 people is shown as the probability for three people and so on.
EDIT(8-31-2015): I also forgot to mention that my Professor stated that my SameBirthday function needed the parameters: birthday[], and numpeople so I cannot use MAX_PEOPLE as a parameter. My professor also suggested using a triple nested for loop within the main body of the function. I believe what is making my output off by one for each person relates to the triple nested for loop, but I am unsure what would cause the issue.
Just do it like this:
bool SameBirthday(int birthdays[], int numPeople)
{
for(int x=0; x<numPeople; x++){
for(int y=0; y<numPeople; y++){
if(birthdays[x] == birthdays[y])
return true;
}
}
return false;
}
Your logic in your nested loop is wrong..
for (SpaceOne = 0; SpaceOne < numpeople - 1; SpaceOne++)
for (SpaceTwo = SpaceOne + 1; SpaceTwo < numpeople; SpaceTwo++)
Your inner loop is skipping n number of checks where n equals SpaceOne.
By the way, this is not C programming. You can declare variable within a for-loop.
I see two problems with the actual functionality. First, SameBirthday needs to return a value (false) when there is no birthday match. You can do that at the end of the function, after all the loops are done.
Second, you need to increment numMatches when you find a match.
To clarify issues from other parts of your coding. I think this is what your school wants.
int main(){
//All your variables
for(int x=0; x<NUM_TRIALS; x++){
for(int y=0; y< MAX_PEOPLE; y++){
birthdays[y] = (rand() % 365 + 1);
}
if(SameBirthday(birthdays, MAX_PEOPLE) == true)
numMatches ++;
}
Probability = ((double)numMatches / NUM_TRIALS);
cout << "For " << people << ", the probability of two birthdays is about "
<< Probability << endl;
}
NUM_TRIALS to generate 5000 datasets. Hence, you generate birthday for 50 students 5000 times. For each trial within a class of 50, you check whether there are 2 person with same birthday. If there is, numMatches + 1.
After 5000 trials, you get the probability.
Your other problem is that numpeople will always be the number of people minus 1. You don't actually need that variable at all. Your "people" variable is the correct number of people.
I'm making a C++ program for the game chopsticks.
It's a really simple game with only 625 total game states (and it's even lower if you account for symmetry and unreachable states). I have read up minimax and alpha-beta algorithms, mostly for tic tac toe, but the problem I was having was that in tic tac toe it's impossible to loop back to a previous state while that can easily happen in chopsticks. So when running the code it would end up with a stack overflow.
I fixed this by adding flags for previously visited states (I don't know if that's the right way to do it.) so that they can be avoided, but now the problem I have is that the output is not symmetric as expected.
For example in the start state of the game each player has one finger so it's all symmetric. The program tells me that the best move is to hit my right hand with my left but not the opposite.
My source code is -
#include <iostream>
#include <array>
#include <vector>
#include <limits>
std::array<int, 625> t; //Flags for visited states.
std::array<int, 625> f; //Flags for visited states.
int no = 0; //Unused. For debugging.
class gamestate
{
public:
gamestate(int x, bool t) : turn(t) //Constructor.
{
for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++) {
val[i][j] = x % 5;
x /= 5;
}
init();
}
void print() //Unused. For debugging.
{
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 2; j++)
std::cout << val[i][j] << "\t";
std::cout << "\n";
}
std::cout << "\n";
}
std::array<int, 6> canmove = {{ 1, 1, 1, 1, 1, 1 }}; //List of available moves.
bool isover() //Is the game over.
{
return ended;
}
bool won() //Who won the game.
{
return winner;
}
bool isturn() //Whose turn it is.
{
return turn;
}
std::vector<int> choosemoves() //Choose the best possible moves in the current state.
{
std::vector<int> bestmoves;
if(ended)
return bestmoves;
std::array<int, 6> scores;
int bestscore;
if(turn)
bestscore = std::numeric_limits<int>::min();
else
bestscore = std::numeric_limits<int>::max();
scores.fill(bestscore);
for (int i = 0; i < 6; i++)
if (canmove[i]) {
t.fill(0);
f.fill(0);
gamestate *play = new gamestate(this->playmove(i),!turn);
scores[i] = minimax(play, 0, std::numeric_limits<int>::min(), std::numeric_limits<int>::max());
std::cout<<i<<": "<<scores[i]<<std::endl;
delete play;
if (turn) if (scores[i] > bestscore) bestscore = scores[i];
if (!turn) if (scores[i] < bestscore) bestscore = scores[i];
}
for (int i = 0; i < 6; i++)
if (scores[i] == bestscore)
bestmoves.push_back(i);
return bestmoves;
}
private:
std::array<std::array<int, 2>, 2 > val; //The values of the fingers.
bool turn; //Whose turn it is.
bool ended = false; //Has the game ended.
bool winner; //Who won the game.
void init() //Check if the game has ended and find the available moves.
{
if (!(val[turn][0]) && !(val[turn][1])) {
ended = true;
winner = !turn;
canmove.fill(0);
return;
}
if (!(val[!turn][0]) && !(val[!turn][1])) {
ended = true;
winner = turn;
canmove.fill(0);
return;
}
if (!val[turn][0]) {
canmove[0] = 0;
canmove[1] = 0;
canmove[2] = 0;
if (val[turn][1] % 2)
canmove[5] = 0;
}
if (!val[turn][1]) {
if (val[turn][0] % 2)
canmove[2] = 0;
canmove[3] = 0;
canmove[4] = 0;
canmove[5] = 0;
}
if (!val[!turn][0]) {
canmove[0] = 0;
canmove[3] = 0;
}
if (!val[!turn][1]) {
canmove[1] = 0;
canmove[4] = 0;
}
}
int playmove(int mov) //Play a move to get the next game state.
{
auto newval = val;
switch (mov) {
case 0:
newval[!turn][0] = (newval[turn][0] + newval[!turn][0]);
newval[!turn][0] = (5 > newval[!turn][0]) ? newval[!turn][0] : 0;
break;
case 1:
newval[!turn][1] = (newval[turn][0] + newval[!turn][1]);
newval[!turn][1] = (5 > newval[!turn][1]) ? newval[!turn][1] : 0;
break;
case 2:
if (newval[turn][1]) {
newval[turn][1] = (newval[turn][0] + newval[turn][1]);
newval[turn][1] = (5 > newval[turn][1]) ? newval[turn][1] : 0;
} else {
newval[turn][0] /= 2;
newval[turn][1] = newval[turn][0];
}
break;
case 3:
newval[!turn][0] = (newval[turn][1] + newval[!turn][0]);
newval[!turn][0] = (5 > newval[!turn][0]) ? newval[!turn][0] : 0;
break;
case 4:
newval[!turn][1] = (newval[turn][1] + newval[!turn][1]);
newval[!turn][1] = (5 > newval[!turn][1]) ? newval[!turn][1] : 0;
break;
case 5:
if (newval[turn][0]) {
newval[turn][0] = (newval[turn][1] + newval[turn][0]);
newval[turn][0] = (5 > newval[turn][0]) ? newval[turn][0] : 0;
} else {
newval[turn][1] /= 2;
newval[turn][0] = newval[turn][1];
}
break;
default:
std::cout << "\nInvalid move!\n";
}
int ret = 0;
for (int i = 1; i > -1; i--)
for (int j = 1; j > -1; j--) {
ret+=newval[i][j];
ret*=5;
}
ret/=5;
return ret;
}
static int minimax(gamestate *game, int depth, int alpha, int beta) //Minimax searching function with alpha beta pruning.
{
if (game->isover()) {
if (game->won())
return 1000 - depth;
else
return depth - 1000;
}
if (game->isturn()) {
for (int i = 0; i < 6; i++)
if (game->canmove[i]&&t[game->playmove(i)]!=-1) {
int score;
if(!t[game->playmove(i)]){
t[game->playmove(i)] = -1;
gamestate *play = new gamestate(game->playmove(i),!game->isturn());
score = minimax(play, depth + 1, alpha, beta);
delete play;
t[game->playmove(i)] = score;
}
else
score = t[game->playmove(i)];
if (score > alpha) alpha = score;
if (alpha >= beta) break;
}
return alpha;
} else {
for (int i = 0; i < 6; i++)
if (game->canmove[i]&&f[game->playmove(i)]!=-1) {
int score;
if(!f[game->playmove(i)]){
f[game->playmove(i)] = -1;
gamestate *play = new gamestate(game->playmove(i),!game->isturn());
score = minimax(play, depth + 1, alpha, beta);
delete play;
f[game->playmove(i)] = score;
}
else
score = f[game->playmove(i)];
if (score < beta) beta = score;
if (alpha >= beta) break;
}
return beta;
}
}
};
int main(void)
{
gamestate test(243, true);
auto movelist = test.choosemoves();
for(auto i: movelist)
std::cout<<i<<std::endl;
return 0;
}
I'm passing the moves in a sort of base-5 to decimal system as each hand can have values from 0 to 4.
In the code I have input the state -
3 3
4 1
The output says I should hit my right hand (1) to the opponent's right (3) but it does not say I should hit it to my opponent's left (also 3)
I think the problem is because of the way I handled infinite looping.
What would be the right way to do it? Or if that is the right way, then how do I fix the problem?
Also please let me know how I can improve my code.
Thanks a lot.
Edit:
I have changed my minimax function as follows to ensure that infinite loops are scored above losing but I'm still not getting symmetry. I also made a function to add depth to the score
static float minimax(gamestate *game, int depth, float alpha, float beta) //Minimax searching function with alpha beta pruning.
{
if (game->isover()) {
if (game->won())
return 1000 - std::atan(depth) * 2000 / std::acos(-1);
else
return std::atan(depth) * 2000 / std::acos(-1) - 1000;
}
if (game->isturn()) {
for (int i = 0; i < 6; i++)
if (game->canmove[i]) {
float score;
if(!t[game->playmove(i)]) {
t[game->playmove(i)] = -1001;
gamestate *play = new gamestate(game->playmove(i), !game->isturn());
score = minimax(play, depth + 1, alpha, beta);
delete play;
t[game->playmove(i)] = score;
} else if(t[game->playmove(i)] == -1001)
score = 0;
else
score = adddepth(t[game->playmove(i)], depth);
if (score > alpha) alpha = score;
if (alpha >= beta) break;
}
return alpha;
} else {
for (int i = 0; i < 6; i++)
if (game->canmove[i]) {
float score;
if(!f[game->playmove(i)]) {
f[game->playmove(i)] = -1001;
gamestate *play = new gamestate(game->playmove(i), !game->isturn());
score = minimax(play, depth + 1, alpha, beta);
delete play;
f[game->playmove(i)] = score;
} else if(f[game->playmove(i)] == -1001)
score = 0;
else
score = adddepth(f[game->playmove(i)], depth);
if (score < beta) beta = score;
if (alpha >= beta) break;
}
return beta;
}
}
This is the function to add depth -
float adddepth(float score, int depth) //Add depth to pre-calculated score.
{
int olddepth;
float newscore;
if(score > 0) {
olddepth = std::tan((1000 - score) * std::acos(-1) / 2000);
depth += olddepth;
newscore = 1000 - std::atan(depth) * 2000 / std::acos(-1);
} else {
olddepth = std::tan((1000 + score) * std::acos(-1) / 2000);
depth += olddepth;
newscore = std::atan(depth) * 2000 / std::acos(-1) - 1000;
}
return newscore;
}
Disclaimer: I don't know C++, and I frankly haven't bothered to read the game rules. I have now read the rules, and still stand by what I said...but I still don't know C++. Still, I can present some general knowledge of the algorithm which should set you off in the right direction.
Asymmetry is not in itself a bad thing. If two moves are exactly equivalent, it should choose one of them and not stand helpless like Buridan's ass. You should, in fact, be sure that any agent you write has some method of choosing arbitrarily between policies which it cannot distinguish.
You should think more carefully about the utility scheme implied by refusing to visit previous states. Pursuing an infinite loop is a valid policy, even if your current representation of it will crash the program; maybe the bug is the overflow, not the policy that caused it. If given the choice between losing the game, and refusing to let the game end, which do you want your agent to prefer?
Playing ad infinitum
If you want your agent to avoid losing at all costs -- that is, you want it to prefer indefinite play over loss -- then I would suggest treating any repeated state as a terminal state and assigning it a value somewhere between winning and losing. After all, in a sense it is terminal -- this is the loop the game will enter forever and ever and ever, and the definite result of it is that there is no winner. However, remember that if you are using simple minimax (one utility function, not two), then this implies that your opponent also regards eternal play as a middling result.
It may sound ridiculous, but maybe playing unto infinity is actually a reasonable policy. Remember that minimax assumes the worst case -- a perfectly rational foe whose interests are the exact opposite of yours. But if, for example, you're writing an agent to play against a human, then the human will either err logically, or will eventually decide they would rather end the game by losing -- so your agent will benefit from patiently staying in this Nash equilibrium loop!
Alright, let's end the game already
If you want your agent to prefer that the game end eventually, then I would suggest implementing a living penalty -- a modifier added to your utility which decreases as a function of time (be it asymptotic or without bound). Implemented carefully, this can guarantee that, eventually, any end is preferable to another turn. With this solution as well, you need to be careful about considering what preferences this implies for your opponent.
A third way
Another common solution is to depth-limit your search and implement an evaluation function. This takes the game state as its input and just spits out a utility value which is its best guess at the end result. Is this provably optimal? No, not unless your evaluation function is just completing the minimax, but it means your algorithm will finish within a reasonable time. By burying this rough estimate deep enough in the tree, you wind up with a pretty reasonable model. However, this produces an incomplete policy, which means that it is more useful for a replanning agent than for a standard planning agent. Minimax replanning is the usual approach for complex games (it is, if I'm not mistaken, the basic algorithm followed by Deep Blue), but since this is a very simple game you probably don't need to take this approach.
A side note on abstraction
Note that all of these solutions are conceptualized as either numeric changes to or estimations of the utility function. This is, in general, preferable to arbitrarily throwing away possible policies. After all, that's what your utility function is for -- any time you make a policy decision on the basis of anything except the numeric value of your utility, you are breaking your abstraction and making your code less robust.