如何使用scanf函数不知道它的类型来读取值 [英] How to use scanf to read a value without knowing its type

问题描述

我是一个初学者的学生。我被要求写转换基于以下规则用户输入的模块：

I'm a beginner student. I was asked to write a module that translates user input based on the following rule:

• 如果字符是字母使它大写

• if character is a letter make it upper case

如果一个字符是数字使它*而不是

if character is a number make it * instead

如果字符是\\，下一个字符将不受影响

if character is a \, the next character will be unaffected

该程序必须继续调用scanf（）的从用户读取字符，直到EOF是encountered.Note：你应尽快打印字符，你得到他们。不要试图拯救他们。

The program must continue to call scanf() to read characters from the user until EOF is encountered.Note: You should be printing characters as soon as you get them. Do not attempt to save them.

例如：

input : Hi Mike your room number is \4\2\3 and the passcode is 312
output: HI MIKE YOUR ROOM NUMBER IS 423 AND THE PASSCODE is ***

现在我的问题是：既然你不知道接下来将进入什么类型的角色呢，你怎么能保存它像一个scanf函数varaible（％C，＆安培; FUNC）保存字符FUNC？另外我不允许使​​用TOUPPER（），所以我怎么能做出一个字母大写？

Now my question is: since you don't know what type of character will be entered next, how can you save it in a varaible like scanf("%c", &func) saves the character in func? Also I'm not allowed to use toupper() so how can I make a letter upper case?

任何帮助是pciated !!谢谢AP $ P $

Any help is appreciated!!Thanks

推荐答案

您必须把它作为一个字符串（或单个字符）第一。然后，您可以检查，如果事情是一个数字比较其ASCII code：

You will have to treat it as a string (or single characters) first. Then, you can check if something is a number by comparing its ASCII code:

if(x >= '0' && x <= '9') // digit

有关的其他条件类似。

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