C ++:为什么空格在读取时总是以字符串结尾? [英] C++: Why does space always terminate a string when read?

问题描述

使用类型 std :: string 接受一个句子，以进行练习(我在C ++中使用字符串的方式不多)，我正在检查字符是否为元音.我知道了:

Using type std::string to accept a sentence, for practice (I haven't worked with strings in C++ much) I'm checking if a character is a vowel or not. I got this:

for(i = 0; i <= analyse.length(); i++) {
if(analyse[i] == 'a' || analyse[i] == 'e' [..etc..]) {
 ...vowels++;    
} else { ...
 ...consonants++;
}

如果字符串全是一个单词，这很好用，但是第二个字符串我加了一个空格(即: aeio aatest )，它只会将第一个块算作一个辅音，并且退出阅读句子(退出for循环之类的东西).

This works fine if the string is all one word, but the second I add a space (IE: aeio aatest) it will only count the first block and count the space as a consonant, and quit reading the sentence (exiting the for loop or something).

空格是否视为无字符==空?还是与 std :: string ?有点奇怪，知道为什么会这样会很有帮助！

Does a space count as no character == null? Or some oddity with std::string?, It would be helpful to know why that is happening!

我只是通过std :: cin接受字符串，例如:

I'm simply accepting the string through std::cin, such as:

std::string analyse = "";
std::cin >> analyse;

推荐答案

我猜您正在使用类似 your_stream>>的字符串读取字符串.your_string; .字符串的运算符>> 定义为(大约)与 scanf 的％s 转换相同，直到读取该转换为止.遇到空格-因此， operator>> 也是一样.

I'd guess you're reading your string with something like your_stream >> your_string;. Operator >> for strings is defined to work (about) the same as scanf's %s conversion, which reads up until it encounters whitespace -- therefore, operator>> does the same.

您可以使用 std :: getline 读取整行输入.您可能还需要查看

You can read an entire line of input instead with std::getline. You might also want to look at an answer I posted to a previous question (provides some alternatives to std::getline).

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