Pygame : Why is giving error everytime i quit the snake game?

Question

Every time i quit the game it gives me this error how can i fix it ?
I've been trying for almost 2 hours to fix it I've been trying to change the last line but still it doesn't quit because there is problem with the loop ? Help please error code:

---

#codes

 import random
 import pygame
 import sys
 from pygame.locals import *

Snakespeed= 17
Window_Width= 800
Window_Height= 500
Cell_Size = 20 #Width and height of the cells
assert Window_Width % Cell_Size == 0, "Window width must be a multiple of cell size."     #Ensuring that the cells fit perfectly in the window. eg if cell size was 10     and window width or windowheight were 15 only 1.5 cells would fit.
assert Window_Height % Cell_Size == 0, "Window height must be a multiple of cell size."  #Ensuring that only whole integer number of cells fit perfectly in the window.
Cell_W= int(Window_Width / Cell_Size) #Cell Width 
Cell_H= int(Window_Height / Cell_Size) #Cellc Height


White= (255,255,255)
Black= (0,0,0)
Red= (255,0,0) #Defining element colors for the program.
Green= (0,255,0)
DARKGreen= (0,155,0)
DARKGRAY= (40,40,40)
YELLOW= (255,255,0)
Red_DARK= (150,0,0)
BLUE= (0,0,255)
BLUE_DARK= (0,0,150)



BGCOLOR = Black # Background color


UP = 'up'
DOWN = 'down'      # Defining keyboard keys.  
LEFT = 'left'
RIGHT = 'right'

HEAD = 0 # Syntactic sugar: index of the snake's head

def main():
global SnakespeedCLOCK, DISPLAYSURF, BASICFONT

pygame.init()
SnakespeedCLOCK = pygame.time.Clock()
DISPLAYSURF = pygame.display.set_mode((Window_Width, Window_Height))
BASICFONT = pygame.font.Font('freesansbold.ttf', 18)
pygame.display.set_caption('Snake')

showStartScreen()
while True:
    runGame()
    showGameOverScreen()


def runGame():
# Set a random start point.
startx = random.randint(5, Cell_W - 6)
starty = random.randint(5, Cell_H - 6)
wormCoords = [{'x': startx,     'y': starty},
              {'x': startx - 1, 'y': starty},
              {'x': startx - 2, 'y': starty}]
direction = RIGHT

# Start the apple in a random place.
apple = getRandomLocation()

while True: # main game loop
    for event in pygame.event.get(): # event handling loop
        if event.type == QUIT:
            terminate()
        elif event.type == KEYDOWN:
            if (event.key == K_LEFT ) and direction != RIGHT:
                direction = LEFT
            elif (event.key == K_RIGHT ) and direction != LEFT:
                direction = RIGHT
            elif (event.key == K_UP ) and direction != DOWN:
                direction = UP
            elif (event.key == K_DOWN ) and direction != UP:
                direction = DOWN
            elif event.key == K_ESCAPE:
                terminate()

    # check if the Snake has hit itself or the edge
    if wormCoords[HEAD]['x'] == -1 or wormCoords[HEAD]['x'] == Cell_W or     wormCoords[HEAD]['y'] == -1 or wormCoords[HEAD]['y'] == Cell_H:
        return # game over 
    for wormBody in wormCoords[1:]:
        if wormBody['x'] == wormCoords[HEAD]['x'] and wormBody['y'] == wormCoords[HEAD]    ['y']: 
            return # game over

    # check if Snake has eaten an apply
    if wormCoords[HEAD]['x'] == apple['x'] and wormCoords[HEAD]['y'] == apple['y']:
        # don't remove worm's tail segment
        apple = getRandomLocation() # set a new apple somewhere
    else:
        del wormCoords[-1] # remove worm's tail segment

    # move the worm by adding a segment in the direction it is moving
    if direction == UP:
        newHead = {'x': wormCoords[HEAD]['x'], 'y': wormCoords[HEAD]['y'] - 1}
    elif direction == DOWN:
        newHead = {'x': wormCoords[HEAD]['x'], 'y': wormCoords[HEAD]['y'] + 1}
    elif direction == LEFT:
        newHead = {'x': wormCoords[HEAD]['x'] - 1, 'y': wormCoords[HEAD]['y']}
    elif direction == RIGHT:
        newHead = {'x': wormCoords[HEAD]['x'] + 1, 'y': wormCoords[HEAD]['y']}
    wormCoords.insert(0, newHead)
    DISPLAYSURF.fill(BGCOLOR)
    drawGrid()
    drawWorm(wormCoords)
    drawApple(apple)
    drawScore(len(wormCoords) - 3)
    pygame.display.update()
    SnakespeedCLOCK.tick(Snakespeed)

def drawPressKeyMsg():
pressKeySurf = BASICFONT.render('Press a key to play.', True, White)
pressKeyRect = pressKeySurf.get_rect()
pressKeyRect.topleft = (Window_Width - 200, Window_Height - 30)
DISPLAYSURF.blit(pressKeySurf, pressKeyRect)


def checkForKeyPress():
if len(pygame.event.get(QUIT)) > 0:
    terminate()
keyUpEvents = pygame.event.get(KEYUP)
if len(keyUpEvents) == 0:
    return None
if keyUpEvents[0].key == K_ESCAPE:
    terminate()
return keyUpEvents[0].key


def showStartScreen():
titleFont = pygame.font.Font('freesansbold.ttf', 100)
titleSurf1 = titleFont.render('Snake!', True, White, DARKGreen)
degrees1 = 0
degrees2 = 0
while True:
    DISPLAYSURF.fill(BGCOLOR)
    rotatedSurf1 = pygame.transform.rotate(titleSurf1, degrees1)
    rotatedRect1 = rotatedSurf1.get_rect()
    rotatedRect1.center = (Window_Width / 2, Window_Height / 2)
    DISPLAYSURF.blit(rotatedSurf1, rotatedRect1)

    drawPressKeyMsg()

    if checkForKeyPress():
        pygame.event.get() # clear event queue
        return
    pygame.display.update()
    SnakespeedCLOCK.tick(Snakespeed)
    degrees1 += 3 # rotate by 3 degrees each frame
    degrees2 += 7 # rotate by 7 degrees each frame


def terminate():
pygame.quit()
sys.exit()


def getRandomLocation():
return {'x': random.randint(0, Cell_W - 1), 'y': random.randint(0, Cell_H - 1)}


def showGameOverScreen():
gameOverFont = pygame.font.Font('freesansbold.ttf', 100)
gameSurf = gameOverFont.render('Game', True, White)
overSurf = gameOverFont.render('Over', True, White)
gameRect = gameSurf.get_rect()
overRect = overSurf.get_rect()
gameRect.midtop = (Window_Width / 2, 10)
overRect.midtop = (Window_Width / 2, gameRect.height + 10 + 25)

DISPLAYSURF.blit(gameSurf, gameRect)
DISPLAYSURF.blit(overSurf, overRect)
drawPressKeyMsg()
pygame.display.update()
pygame.time.wait(500)
checkForKeyPress() # clear out any key presses in the event queue

while True:
    if checkForKeyPress():
        pygame.event.get() # clear event queue
        return

def drawScore(score):
scoreSurf = BASICFONT.render('Score: %s' % (score), True, White)
scoreRect = scoreSurf.get_rect()
scoreRect.topleft = (Window_Width - 120, 10)
DISPLAYSURF.blit(scoreSurf, scoreRect)


def drawWorm(wormCoords):
for coord in wormCoords:
    x = coord['x'] * Cell_Size
    y = coord['y'] * Cell_Size
    wormSegmentRect = pygame.Rect(x, y, Cell_Size, Cell_Size)
    pygame.draw.rect(DISPLAYSURF, DARKGreen, wormSegmentRect)
    wormInnerSegmentRect = pygame.Rect(x + 4, y + 4, Cell_Size - 8, Cell_Size - 8)
    pygame.draw.rect(DISPLAYSURF, Green, wormInnerSegmentRect)


def drawApple(coord):
x = coord['x'] * Cell_Size
y = coord['y'] * Cell_Size
appleRect = pygame.Rect(x, y, Cell_Size, Cell_Size)
pygame.draw.rect(DISPLAYSURF, Red, appleRect)


def drawGrid():
for x in range(0, Window_Width, Cell_Size): # draw vertical lines
    pygame.draw.line(DISPLAYSURF, DARKGRAY, (x, 0), (x, Window_Height))
for y in range(0, Window_Height, Cell_Size): # draw horizontal lines
    pygame.draw.line(DISPLAYSURF, DARKGRAY, (0, y), (Window_Width, y))




if __name__ == '__main__':
main()

Answer 1

When you call the command:

sys.exit()

It raises a SystemExit exception, telling the program to end.

If it's important for you to avoid a traceback in whichever environment you're running it, you should catch that exception at the top. For instance, you have this at the bottom:

if __name__ == '__main__':
    main()

Change it to handle any SystemExit exception raised in main() :

if __name__ == '__main__':
    try:
        main()
    except SystemExit:
        pass

Because that's the end of your program anyway, it will still exit, but naturally

Answer 2

That's NOT an error. This is done by the sys.exit() command. If you want to avoid it, just keep a flag variable. In the mainloop, change the while syntax to while not gameover : and on terminate() , change the sys.exit() to gameover=True . Donot forget to add a global variable called gameover with a default value of False

Answer 3

sys.exit()

exits the program. Run your program in the command line and it should work. Instead of running it in IDLE, double click it from your file explorer