DEV Community: Ilya

Tic-tac-toe in Python

Ilya — Mon, 08 Nov 2021 17:23:31 +0000

Today we are faced with the task of writing a game of tic-tac-toe on python. Recall that tic-tac-toe is a logical game for two players on a 3x3 square field.

To begin with, we will set the field. Our field will be a one-dimensional list with numbers from 1 to 9. To create it, we will use the range() function

board = range(1,10)

Now let's write a function that will output our field in the usual format

def draw_board(board): print "-------------" for i in range(3): print "|", board[0+i*3], "|", board[1+i*3], "|", board[2+i*3], "|" print "-------------"

It's time to allow users to enter data into our game. Writing the take_input function

ef take_input(player_token): valid = False while not valid: player_answer = raw_input("Where do we put " + player_token+"? ") try: player_answer = int(player_answer) except: print "Incorrect input. Are you sure you entered a number?" continue if player_answer >= 1 and player_answer <= 9: if (str(board[player_answer-1]) not in "XO"): board[player_answer-1] = player_token valid = True else: print "This cell is already occupied" else: print "Incorrect input. Enter a number from 1 to 9 to be like."

As you can see, the take_input function takes the player_token parameter - a cross or a toe, depending on whose turn it is now. We need to limit the user's choice to numbers from 1 to 9. To do this, we use the try/except and if/else constructs to make sure that the selected cell is not occupied. Note that the take_input function does not return any value, but only modifies the existing board list.

It remains to write a function for checking the playing field. Let's call this function check_win.

def check_win(board): win_coord = ((0,1,2),(3,4,5),(6,7,8),(0,3,6),(1,4,7),(2,5,8),(0,4,8),(2,4,6)) for each in win_coord: if board[each[0]] == board[each[1]] == board[each[2]]: return board[each[0]] return False

Checking the results of the tic-tac-toe game is a fairly common programming task. As often happens, the same task in programming can be solved in several ways. In this case, we simply created a tuple with the winning coordinates and ran a for loop through it. If the symbols in all three specified cells are equal, we return the winning symbol, otherwise, we return the value False. At the same time, it is important to remember that not an empty string (our winning symbol) when converting it to a logical type, it will return True (we will need this in the future).

It remains to create the main function, in which we will put together all the described functions.

def main(board): counter = 0 win = False while not win: draw_board(board) if counter % 2 == 0: take_input("X") else: take_input("O") counter += 1 if counter > 4: tmp = check_win(board) if tmp: print tmp, "won!" win = True break if counter == 9: print "drawn game!" break draw_board(board)def main(board): counter = 0 win = False while not win: draw_board(board) if counter % 2 == 0: take_input("X") else: take_input("O") counter += 1 if counter > 4: tmp = check_win(board) if tmp: print tmp, "won!" win = True break if counter == 9: print "drawn game!" break draw_board(board)

The operation of the main function is extremely clear, except that lines 45 and 46 may cause misunderstanding. We are waiting for the counter variable to become greater than 4 to avoid a deliberately unnecessary call to the check_win function (no one can win for sure until the fifth movie). The tmp variable was created again in order not to call the check_in function once again, we just "remember" its value and, if necessary, use it on line 48. The benefits of this approach are not so noticeable when working with small amounts of data, but in general, such savings in processor time are good practice.

Now we can safely play by running the main(board)

Have a good game!

the Snake game in Python

Ilya — Sat, 06 Nov 2021 20:50:06 +0000

1. Installing Pygame

The first thing we need to do is install the Pygame library. This can be done by simply running the following command:

pip install pygame

After doing this, just import this library and start developing the game. But before that, let's take a look at the main functions of this library, which we will use when creating a game.

Function	Description
init()	Initializes all Pygame modules (returns a tuple in case of success or failure).
display.set_mode()	To create a surface, it takes either a list or a tuple as a parameter (a tuple is preferable).
update()	Refreshes the screen.
quit()	Used to initialize all modules.
set_caption()	Sets the title text at the top of the screen
event.get()	Returns a list of all events.
Surface.fill()	Fills the space with a solid colour.
time.Clock()	Time tracking
font.SysFont()	Sets the Pygame font using system resources.

2. Creating a screen

To create a screen using Pygame, you need to use the display.set_mode() function. You also need to use the init() method to initialize the screen at the beginning of the code and the quit() method to close it at the end. The update() method is used to apply any changes to the screen. There is also a flip() method that works in a similar way to update(). The only difference is that the flip() method rewrites the entire screen, and the update() method applies exactly the changes (although if it is used without parameters, it also rewrites the entire screen).

import pygame pygame.init() dis=pygame.display.set_mode((400,300)) pygame.display.update() pygame.quit() quit()

However, when you run this code, the screen will appear only for a moment, and then disappear. To fix this error, we will use the while loop, which will run until the end of the game:

import pygame pygame.init() dis=pygame.display.set_mode((400,300)) pygame.display.update() pygame.display.set_caption('Snake game by Pythonist') game_over=False while not game_over: for event in pygame.event.get(): print(event) pygame.quit() quit()

Now, by running this code, you will see that the screen does not disappear as before. It will display all the actions of the game. We achieved this thanks to the event.get() function. Also, using the display.set_caption() function, we displayed the title of our screen — 'Snake game by Pythonist’.
Now we have a screen for the game, but when you click on the close button, the screen will not close. This is because we have not provided for such behaviour. To solve this problem, Pygame provides a "QIUT" event, which we use as follows:

import pygame pygame.init() dis=pygame.display.set_mode((400,300)) pygame.display.update() pygame.display.set_caption('Snake game by Edureka') game_over=False while not game_over: for event in pygame.event.get(): if event.type==pygame.QUIT: game_over=True pygame.quit() quit()

Now that our screen is fully prepared, we have to draw a snake on it. The following section is devoted to this.

3. Creating a snake

Before creating a snake, we initiate several colour variables to colourize the snake itself, the food and the screen. Pygame uses the RGB colour scheme (RED, GREEN, BLUE). Setting all colors to 0 corresponds to black, and 255 corresponds to white, respectively.
In fact, our snake is a rectangle. To draw a rectangle in Pygame, you can use the draw.rect() function, which will draw us a rectangle of a given color and size.

import pygame pygame.init() dis=pygame.display.set_mode((400,300)) pygame.display.set_caption('Snake game by Pythonist') blue=(0,0,255) red=(255,0,0) game_over=False while not game_over: for event in pygame.event.get(): if event.type==pygame.QUIT: game_over=True pygame.draw.rect(dis,blue,[200,150,10,10]) pygame.display.update() pygame.quit() quit()

As you can see, the snake is created in the form of a blue rectangle. Now we need to teach her to move.

4. Snake Movement

To move the snake, we will use key events from the KEYDOWN class of the Pygame library. The K_UP, K_DOWN, K_LEFT, and K_RIGHT events will cause the snake to move up, down, left, and right, respectively. Also, the display colour changes from black (by default) to white using the fill() method.
To save the x and y coordinate changes, we have created two new variables: x1_change and y1_change.

import pygame pygame.init() white = (255, 255, 255) black = (0, 0, 0) red = (255, 0, 0) dis = pygame.display.set_mode((800, 600)) pygame.display.set_caption('Snake game by Pythonist') game_over = False x1 = 300 y1 = 300 x1_change = 0 y1_change = 0 clock = pygame.time.Clock() while not game_over: for event in pygame.event.get(): if event.type == pygame.QUIT: game_over = True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: x1_change = -10 y1_change = 0 elif event.key == pygame.K_RIGHT: x1_change = 10 y1_change = 0 elif event.key == pygame.K_UP: y1_change = -10 x1_change = 0 elif event.key == pygame.K_DOWN: y1_change = 10 x1_change = 0 x1 += x1_change y1 += y1_change dis.fill(white) pygame.draw.rect(dis, black, [x1, y1, 10, 10]) pygame.display.update() clock.tick(30) pygame.quit() quit()

5. "Game over" when the snake reaches the border.

In the snake game, the player loses if he touches the border of the screen. To set this behaviour, we must use the if statement, which will make sure that the x and y coordinates are smaller than the screen size. We will use variables for this, so that you can then, on occasion, easily make any changes to the game.

import pygame import time pygame.init() white = (255, 255, 255) black = (0, 0, 0) red = (255, 0, 0) dis_width = 800 dis_height = 600 dis = pygame.display.set_mode((dis_width, dis_width)) pygame.display.set_caption('Snake game by Pythonist') game_over = False x1 = dis_width/2 y1 = dis_height/2 snake_block=10 x1_change = 0 y1_change = 0 clock = pygame.time.Clock() snake_speed=30 font_style = pygame.font.SysFont(None, 50) def message(msg,color): mesg = font_style.render(msg, True, color) dis.blit(mesg, [dis_width/2, dis_height/2]) while not game_over: for event in pygame.event.get(): if event.type == pygame.QUIT: game_over = True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: x1_change = -snake_block y1_change = 0 elif event.key == pygame.K_RIGHT: x1_change = snake_block y1_change = 0 elif event.key == pygame.K_UP: y1_change = -snake_block x1_change = 0 elif event.key == pygame.K_DOWN: y1_change = snake_block x1_change = 0 if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0: game_over = True x1 += x1_change y1 += y1_change dis.fill(white) pygame.draw.rect(dis, black, [x1, y1, snake_block, snake_block]) pygame.display.update() clock.tick(snake_speed) message("You lost",red) pygame.display.update() time.sleep(2) pygame.quit() quit()

6. Adding Food

Now we will add some food for the snake, and when it crosses it, we will display the message "Yummy!! In addition, we will make small changes that will allow the player to stop the game, as well as start it again in case of defeat.

import pygame import time import random pygame.init() white = (255, 255, 255) black = (0, 0, 0) red = (255, 0, 0) blue = (0, 0, 255) dis_width = 800 dis_height = 600 dis = pygame.display.set_mode((dis_width, dis_height)) pygame.display.set_caption('Snake Game by Edureka') clock = pygame.time.Clock() snake_block = 10 snake_speed = 30 font_style = pygame.font.SysFont(None, 30) def message(msg, color): mesg = font_style.render(msg, True, color) dis.blit(mesg, [dis_width/3, dis_height/3]) def gameLoop(): # creating a function game_over = False game_close = False x1 = dis_width / 2 y1 = dis_height / 2 x1_change = 0 y1_change = 0 foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0 foody = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0 while not game_over: while game_close == True: dis.fill(white) message("You Lost! Press Q-Quit or C-Play Again", red) pygame.display.update() for event in pygame.event.get(): if event.type == pygame.KEYDOWN: if event.key == pygame.K_q: game_over = True game_close = False if event.key == pygame.K_c: gameLoop() for event in pygame.event.get(): if event.type == pygame.QUIT: game_over = True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: x1_change = -snake_block y1_change = 0 elif event.key == pygame.K_RIGHT: x1_change = snake_block y1_change = 0 elif event.key == pygame.K_UP: y1_change = -snake_block x1_change = 0 elif event.key == pygame.K_DOWN: y1_change = snake_block x1_change = 0 if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0: game_close = True x1 += x1_change y1 += y1_change dis.fill(white) pygame.draw.rect(dis, blue, [foodx, foody, snake_block, snake_block]) pygame.draw.rect(dis, black, [x1, y1, snake_block, snake_block]) pygame.display.update() if x1 == foodx and y1 == foody: print("Yummy!!") clock.tick(snake_speed) pygame.quit() quit() gameLoop()

7. Increasing the length of the snake

The following code will increase the length of the snake after it has absorbed food. Also, if the snake collides with its tail, the game ends and the message is displayed“ "You Lost! Press Q-Quit or C-Play Again“. The length of the snake is stored in the list, and the base values are set in the following code.

```import pygame
import time
import random
pygame.init()
white = (255, 255, 255)
yellow = (255, 255, 102)
black = (0, 0, 0)
red = (213, 50, 80)
green = (0, 255, 0)
blue = (50, 153, 213)
dis_width = 600
dis_height = 400
dis = pygame.display.set_mode((dis_width, dis_height))
pygame.display.set_caption('Snake Game by Pythonist')
clock = pygame.time.Clock()
snake_block = 10
snake_speed = 15
font_style = pygame.font.SysFont("bahnschrift", 25)
score_font = pygame.font.SysFont("comicsansms", 35)
def our_snake(snake_block, snake_list):
for x in snake_list:
pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block])
def message(msg, color):
mesg = font_style.render(msg, True, color)
dis.blit(mesg, [dis_width / 6, dis_height / 3])
def gameLoop():
game_over = False
game_close = False
x1 = dis_width / 2
y1 = dis_height / 2
x1_change = 0
y1_change = 0
snake_List = []
Length_of_snake = 1
foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0
foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0
while not game_over:
while game_close == True:
dis.fill(blue)
message("You Lost! Press C-Play Again or Q-Quit", red)
pygame.display.update()
for event in pygame.event.get():
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_q:
game_over = True
game_close = False
if event.key == pygame.K_c:
gameLoop()
for event in pygame.event.get():
if event.type == pygame.QUIT:
game_over = True
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
x1_change = -snake_block
y1_change = 0
elif event.key == pygame.K_RIGHT:
x1_change = snake_block
y1_change = 0
elif event.key == pygame.K_UP:
y1_change = -snake_block
x1_change = 0
elif event.key == pygame.K_DOWN:
y1_change = snake_block
x1_change = 0

    if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0:
        game_close = True
    x1 += x1_change
    y1 += y1_change
    dis.fill(blue)
    pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block])
    snake_Head = []
    snake_Head.append(x1)
    snake_Head.append(y1)
    snake_List.append(snake_Head)
    if len(snake_List) > Length_of_snake:
        del snake_List[0]
    for x in snake_List[:-1]:
        if x == snake_Head:
            game_close = True
    our_snake(snake_block, snake_List)
    pygame.display.update()
    if x1 == foodx and y1 == foody:
        foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0
        foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0
        Length_of_snake += 1
    clock.tick(snake_speed)
pygame.quit()
quit()

gameLoop()```

8. Displaying the invoice on the screen

Last but not least, you need to display the player's score. To do this, we created the Your_score function. This function will show the size of the snake minus 1 (since this is the initial size of the snake).

import pygame import time import random pygame.init() white = (255, 255, 255) yellow = (255, 255, 102) black = (0, 0, 0) red = (213, 50, 80) green = (0, 255, 0) blue = (50, 153, 213) dis_width = 600 dis_height = 400 dis = pygame.display.set_mode((dis_width, dis_height)) pygame.display.set_caption('Snake Game by Pythonist') clock = pygame.time.Clock() snake_block = 10 snake_speed = 15 font_style = pygame.font.SysFont("bahnschrift", 25) score_font = pygame.font.SysFont("comicsansms", 35) def Your_score(score): value = score_font.render("Your Score: " + str(score), True, yellow) dis.blit(value, [0, 0]) def our_snake(snake_block, snake_list): for x in snake_list: pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block]) def message(msg, color): mesg = font_style.render(msg, True, color) dis.blit(mesg, [dis_width / 6, dis_height / 3]) def gameLoop(): game_over = False game_close = False x1 = dis_width / 2 y1 = dis_height / 2 x1_change = 0 y1_change = 0 snake_List = [] Length_of_snake = 1 foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0 foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0 while not game_over: while game_close == True: dis.fill(blue) message("You Lost! Press C-Play Again or Q-Quit", red) Your_score(Length_of_snake - 1) pygame.display.update() for event in pygame.event.get(): if event.type == pygame.KEYDOWN: if event.key == pygame.K_q: game_over = True game_close = False if event.key == pygame.K_c: gameLoop() for event in pygame.event.get(): if event.type == pygame.QUIT: game_over = True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: x1_change = -snake_block y1_change = 0 elif event.key == pygame.K_RIGHT: x1_change = snake_block y1_change = 0 elif event.key == pygame.K_UP: y1_change = -snake_block x1_change = 0 elif event.key == pygame.K_DOWN: y1_change = snake_block x1_change = 0 if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0: game_close = True x1 += x1_change y1 += y1_change dis.fill(blue) pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block]) snake_Head = [] snake_Head.append(x1) snake_Head.append(y1) snake_List.append(snake_Head) if len(snake_List) > Length_of_snake: del snake_List[0] for x in snake_List[:-1]: if x == snake_Head: game_close = True our_snake(snake_block, snake_List) Your_score(Length_of_snake - 1) pygame.display.update() if x1 == foodx and y1 == foody: foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0 foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0 Length_of_snake += 1 clock.tick(snake_speed) pygame.quit() quit() gameLoop()

How to raise to a degree in C++?

Ilya — Sat, 06 Nov 2021 19:27:36 +0000

To raise a number to a power in C++, it is enough to use the pow function, which is located in the math.h library.

The pow function takes two arguments: a number for exponentiation and an exponent of
double pow (double base, double exponent);

Sample code:

include

using namespace std;

int main ()
{
printf ("%g",pow(3,5));
return 0;
}

The result of this program will be the output of the number 243, which is 3 to the 5th power.