Basic Pascal Tutorial/Chapter 2/Input/zh CN: what changed
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Title: Basic Pascal Tutorial/Chapter 2/Input/zh CN
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| 1 | + | 2A - 输入 (原作者: Tao Yue, 状态: 已更改) | |
| 2 | + | ||
| 3 | + | 程序可以接收来自键盘、鼠标、文件、扫描仪、操纵杆的数据。 | |
| 4 | + | ||
| 5 | + | 我们不能得到鼠标的输入，因为语法不同。另外，现在视窗操作系统都支持事件驱动，它们可处理鼠标的输入。 | |
| 6 | + | ||
| 7 | + | 用于读取数据的基本格式是： | |
| 8 | + | ||
| 9 | + | ``` pascal | |
| 10 | + | read (变量列表); | |
| 11 | + | readln (变量列表); | |
| 12 | + | readln; | |
| 13 | + | ``` | |
| 14 | + | ||
| 15 | + | 变量列表是一系列以逗号分隔的变量标识符。 | |
| 16 | + | ||
| 17 | + | 写在括号中的变量，都需要预告先定义；变量与变量之间，以“,”分隔。 | |
| 18 | + | ||
| 19 | + | 从键盘接收数据时，要注意各种不同数据类型数据的分隔符不同。所谓分隔符就是两个完整的数值之间的标记，也可以这样理解，当计算机从键盘读入数据时，一旦碰到分隔符，就认为当前的数据读入已完成，可以把它赋给相应的变量了。各种数据类型的分隔符如下： | |
| 20 | + | ||
| 21 | + | 数值型（包括整型、实型以及它们的子界类型）以空格或回车符作为分隔符； 字符型不需分隔符（因为字符型数据的长度固定，只有一个）； 字符串以回车符作为分隔符。 | |
| 22 | + | ||
| 23 | + | 若多输入了数据(即数据个数超过变量个数)，read语句读完数据之后，能让后续的读语句接着读取多下来的数据；而readln 语句对本行多输入的数据不能让后续语句接着读取多下来的数据。为了防止多输入的数据影响下一个输入语句读取数据，建议尽量使用readln语句输入数据。 | |
| 24 | + | ||
| 25 | + | 假设让用户输入4个整数，a、b、c、d： | |
| 26 | + | ||
| 27 | + | `45 97 3`\ | |
| 28 | + | `1 2 3` | |
| 29 | + | ||
| 30 | + | 下面是`read`和`readln`语句，以及读取相应变量的值。 | |
| 31 | + | ||
| 32 | + | <table> | |
| 33 | + | <thead> | |
| 34 | + | <tr> | |
| 35 | + | <th>声明</th> | |
| 36 | + | <th>a</th> | |
| 37 | + | <th>b</th> | |
| 38 | + | <th>c</th> | |
| 39 | + | <th>d</th> | |
| 40 | + | </tr> | |
| 41 | + | </thead> | |
| 42 | + | <tbody> | |
| 43 | + | <tr> | |
| 44 | + | <td>read (a);</td> | |
| 45 | + | <td rowspan="2">45</td> | |
| 46 | + | <td rowspan="2">97</td> | |
| 47 | + | <td rowspan="2"></td> | |
| 48 | + | <td rowspan="2"></td> | |
| 49 | + | </tr> | |
| 50 | + | <tr> | |
| 51 | + | <td>read (b);</td> | |
| 52 | + | </tr> | |
| 53 | + | <tr> | |
| 54 | + | <td>readln (a);</td> | |
| 55 | + | <td rowspan="2">45</td> | |
| 56 | + | <td rowspan="2" style="text-align: right;">1</td> | |
| 57 | + | <td rowspan="2"></td> | |
| 58 | + | <td rowspan="2"></td> | |
| 59 | + | </tr> | |
| 60 | + | <tr> | |
| 61 | + | <td>read (b);</td> | |
| 62 | + | </tr> | |
| 63 | + | <tr> | |
| 64 | + | <td>read (a, b, c, d);</td> | |
| 65 | + | <td>45</td> | |
| 66 | + | <td>97</td> | |
| 67 | + | <td>3</td> | |
| 68 | + | <td>1</td> | |
| 69 | + | </tr> | |
| 70 | + | <tr> | |
| 71 | + | <td>readln (a, b);</td> | |
| 72 | + | <td rowspan="2">45</td> | |
| 73 | + | <td rowspan="2">97</td> | |
| 74 | + | <td rowspan="2">1</td> | |
| 75 | + | <td rowspan="2">2</td> | |
| 76 | + | </tr> | |
| 77 | + | <tr> | |
| 78 | + | <td>readln (c, d);</td> | |
| 79 | + | </tr> | |
| 80 | + | </tbody> | |
| 81 | + | </table> | |
| 82 | + | ||
| 83 | + | 定义的变量列表，只能是变量，不能是[[Basic Pascal Tutorial/Chapter 1/Constants/zh CN|常量]]。 | |
| 84 | + | ||
| 85 | + | # 外部链接 | |
| 86 | + | ||
| 87 | + | [Read和ReadLn的区别](http://blog.csdn.net/JADE_BLACK/article/details/4087581) | |
| 88 | + | ||
| 89 | + | | | | | | |
| 90 | + | |----|----|----| | |
| 91 | + | | [[Basic Pascal Tutorial/Chapter 1/Solution/zh CN|上一页]] | [[Basic Pascal Tutorial/Contents/zh CN|目录]] | [[Basic Pascal Tutorial/Chapter 2/Output/zh CN|下一页]] | | |
| 92 | + | ||
| 93 | + | --- | |
| 94 | + | *From the Free Pascal wiki, page "Basic Pascal Tutorial/Chapter 2/Input/zh CN", as it stood on 2022-08-20 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).* |