真正容易c ++：操作符>>在fstream中读取东西后删除换行符？ [英] really easy c++: Does the operator >> in fstream remove newline characters after reading something?

问题描述

// file.in
12
13

// main.cpp
fstream f("file.in", ios::in);
int n;
char c;
f >> n;
f.get(&c);

提取数字12后，下一个字符是什么？是换行还是1？如果我调用get的getline instread，是否得到一个空行或'13'？

After extracting the number 12, what is the next character? Is it newline or '1'? If I call getline instread of get, do I get an empty line or '13'?

推荐答案

输入缓冲区，所以你读的下一个字符将是一个新行。但是，请注意，大多数提取器会跳过它们提取的任何内容之前的空格（其中包括换行符），所以除非你调用类似 getline 这通常不会显示。

It leaves the delimiter in the input buffer, so the next character you read will be a new-line. Note, however, that most extractors will skip white space (which includes new-line) before anything they extract, so unless you do call something like getline this won't usually be visible.

编辑：测试像ideone， code> stringstream ：

to test on something like ideone, consider using a stringstream:

#include <sstream>
#include <iostream>

int main(){ 
    std::istringstream f("12\n13");
    int n;
    char c;
    f >> n;
    f.get(c); // get takes a reference, not a pointer. Don't take the address.

    std::cout << "'" << c << "'";
    return 0;
}

我不希望看到一个 stringstream 和 fstream 。

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