在 C++ 中的同一行上打印
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Printing on same line in c++
提问by Zach Starnes
I am trying to write the time on the same line instead of it stacking the outputs. I can not seem to get it to work though.
我试图将时间写在同一行上，而不是将输出堆叠起来。我似乎无法让它工作。
Here is what I have: I thought the "\r"would make it reprint on the same line, but this doesn't work. And I also tried printf("\r");and that didn't work either.
这是我所拥有的：我认为"\r"这会使它在同一行上重印，但这不起作用。而且我也试过了printf("\r");，也没用。
Can anyone help me figure out how to get this to work?
谁能帮我弄清楚如何让它发挥作用？
void countdown(int time)
{
int h = (time / 3600);
int m = (time / 60) - (h * 60);
int s = time % 60;
std::stringstream ss;
ss << h << ":" << m << ":" << s;
std::string string = ss.str();
cout << "\r" << string << endl;
}
回答by Tony Delroy
cout << "\r" << string << endl;
endlmoves the cursor to the next line. Try replacing it with std::flushwhich just ensures output's sent towards the terminal. (You should also #include <iomanip>and use std::setw(2)/ std::setfill('0')to ensure the text you display is constant width, otherwise say the time moves from:
endl将光标移动到下一行。尝试将其替换为std::flush确保输出发送到终端。（您还应该#include <iomanip>使用std::setw(2)/std::setfill('0')来确保您显示的文本宽度恒定，否则说时间从：
23:59:59
to
到
0:0:0
The trailing ":59" from the earlier time is not currently being overwritten or cleared (you could write a few spaces or send a clear-to-end-of-line character sequence if your terminal has one, but fixed-width makes more sense).
较早时间的尾随“:59”当前没有被覆盖或清除（如果您的终端有一个空格，您可以写几个空格或发送一个清除到行尾的字符序列，但固定宽度会使更多感觉）。
So ultimately:
所以最终：
std::cout << '\r'
<< std::setw(2) << std::setfill('0') << h << ':'
<< std::setw(2) << m << ':'
<< std::setw(2) << s << std::flush;
回答by michaeltang
endlinserts a new-line character and flushes the stream.
endl插入一个换行符并刷新流。
cout << "\r" << string ; //works
回答by songyuanyao
try this:
尝试这个：
cout << "\r" << string;
endlinserts a new-line character and flushes the stream.
endl插入一个换行符并刷新流。
回答by Volkan Güven
I want to provide some useful information first.
我想先提供一些有用的信息。
You are inserting std::endlwhich prints next string on the next line.
您正在插入std::endl它在下一行打印下一个字符串。
std::endlis a newline \nfollowed by std::flush
std::endl是一个换行符，\n后跟std::flush
The following newline \nand std::flushis equivalent to std::endl.
下面的换行符\n和std::flush等价于std::endl.
std::cout << printFunction() << '\n' << std::flush;
is just like
就像
std::cout << printFunction() << std::endl;
Now removing std::endlwill print the string in the same line.
现在删除std::endl将在同一行中打印字符串。
cout << "\r" << string;
