Python：游戏：测试打字速度

现在写书的人真是一点责任心都没有，最近看了几本书，其中的代码都存在错误。

最近迷恋 Python 游戏，买了《Python游戏编程入门》[美] Jonathan S·Harbour 著 一书来看。

其中第四章：Bomb Catcher游戏中，测试打字速度的程序代码严重有误。

改程序屏幕上随机显示一个字母，按键输入该字母后随机显示下一个，计算平均一分钟可以输入多少个字母，原代码中计算速度的一块有误，附上我修改后的代码

1import sys
2import random
3import time
4import pygame
5from pygame.locals import *
6
7
8def print_text(font, x, y, text, color=(255, 255, 255)):
9    imgText = font.render(text, True, color)
10    screen.blit(imgText, (x, y))
11
12
13pygame.init()
14screen = pygame.display.set_mode((600, 500))
15pygame.display.set_caption('Keyboard Demo')
16font1 = pygame.font.Font(None, 24)
17font2 = pygame.font.Font(None, 200)
18white = (255, 255, 255)
19yellow = (255, 255, 0)
20
21key_flag = False
22correct_answer = 97     # a
23seconds = 11
24score = 0
25speed = 0
26clock_start = 0
27game_over = True
28
29while True:
30    for event in pygame.event.get():
31        if event.type == QUIT:
32            sys.exit()
33        elif event.type == KEYDOWN:
34            key_flag = True
35        elif event.type == KEYUP:
36            key_flag = False
37
38    keys = pygame.key.get_pressed()     # keys 是一个元组，穷举了所有的按键，未按下为 0，按下为 1
39    if keys[K_ESCAPE]:
40        sys.exit()
41    if keys[K_RETURN]:
42        if game_over:
43            game_over = False
44            clock_start = time.time()
45            score = 0
46            seconds = 11
47            speed = 0
48            clock = clock_start
49
50    if not game_over:
51        current = time.time() - clock_start
52        if seconds < current:
53            game_over = True
54        else:
55            if keys[correct_answer]:
56                correct_answer = random.randint(97, 122)
57                clock_start = time.time()
58                score += 1
59                speed = 60 * score / (clock_start - clock)
60
61    screen.fill((0, 100, 0))
62    print_text(font1, 0, 0, "Let's see how fast you can type!")
63    print_text(font1, 0, 20, "Try to keep up for 10 seconds...")
64
65    if key_flag:
66        print_text(font1, 500, 0, "<key>")
67
68    if not game_over:
69        print_text(font1, 0, 80, "Time: " + str(int(seconds-current)))
70
71    print_text(font1, 0, 100, "Speed: " + str(int(speed)) + " letters/min")
72
73    if game_over:
74        print_text(font1, 0, 160, "Press Enter to start...")
75
76    print_text(font2, 0, 240, chr(correct_answer-32), yellow)
77
78    pygame.display.update()