C++ 使用 cin.get 获取整数
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Using cin.get to get an integer
提问by Quaker
I want to get a string of numbers one by one, so I'm using a whileloop
with cin.get()as the function that gets my digits one by one.
我想一个一个地得到一串数字，所以我使用了一个while循环cin.get()作为一个一个一个地得到我的数字的函数。
But cin.get()gets the digits as chars and even though I'm trying to use
casting I can't get my variables to contain the numrical value and not the ascii value
of the numbers I get as an input.
但是cin.get()将数字作为chars ，即使我尝试使用强制转换，我也无法让我的变量包含数值，而不是我作为输入获得的数字的 ascii 值。
回答by Konrad Rudolph
cin.getcan't parse numbers. You could do it manually –?but why bother re-implementing this function, since it already exists?*
cin.get无法解析数字。你可以手动完成——但为什么要重新实现这个函数，因为它已经存在了？*
int number;
std::cin >> number;
In general, the stream operators (<<and >>) take care of formattedoutput and input, istream::geton the other hand extracts raw characters only.
一般来说，流操作符（<<和>>）负责格式化输出和输入，istream::get另一方面只提取原始字符。
*Of course, if you haveto re-implement this functionality, there's nothing for it.
*当然，如果你必须重新实现这个功能，那就没有办法了。
To get the numeric value from a digit character, you can exploit that the character codes of the decimal digits 0–9 are consecutive. So the following function can covert them:
要从数字字符中获取数值，可以利用十进制数字 0-9 的字符代码是连续的。所以下面的函数可以隐藏它们：
int parse_digit(char digit) {
return digit - '0';
}
