复活的cin [英] resurrecting cin
问题描述
大家好，
我刚刚发现（对我自己）该程序：
// ********* *****************************
#include< iostream>
int main（）
{
int a = 0;
while（true）
{
std :: cout<< 输入一个数字!!! \ n << std :: endl;
std :: cin>> a; ///这里我输入a例如char
if（！std :: cin）
{
std :: cout<<" Oouch，你还没有收听我......我快死了...... \ n" ;;
std :: cin.clear（）; ///我想再转一圈而不是
周期永恒
}
std :: cout<< a<< ;" \ n";
}
返回0;
}
// *** ***************************************
永远循环如果我输入一些字符而不是数字。快看一下
书籍没有向我展示任何解决方案，而是输入一些
字符串然后解析。所有我想要的只是复活cin来制作
另一个回合，是否可能？
-
float_dublin
float_dublin写道：大家好，
我刚刚发现（对我自己）该程序：
// ************************************** #include< iostream>
int a = 0;
while（true）
{
std :: cout<< 输入一个数字!!! \ n << std :: endl;
std :: cin>> a; ///这里我输入a例如char
if（！std :: cin）
{
std :: cout<<" Oouch，你没有听我说......我快死了...... 。\ n";
std :: cin.clear（）; ///我想再转一圈而不是永久循环
//你需要做同步
std :: cin.sync（）; }
std :: cout<< a<<" \ n" ;;
}
返回0;
}
// **** **************************************如果我输入一些字符，我将永远循环数字。快速浏览书籍没有向我展示任何解决方案，而是输入一些
字符串然后解析。我想要的只是复活cin来再次转弯，是否可能？
-
float_dublin
float_dublin写道：
大家好，
我刚刚发现（对我自己）该程序：
// * *************************************
#include< iostream>
int main（）
{a / 0;
while（true）
{
std :: cout<< 输入一个数字!!! \ n << std :: endl;
std :: cin>> a; ///这里我输入a例如char
if（！std :: cin）
{
std :: cout<<" Oouch，你没有听我说......我快死了...... 。\ n";
std :: cin.clear（）; ///我想再转一圈而不是永恒的周期
}
std :: cout<< a<<" \\\
" ;;
}
返回0;
}
// *******************************如果我输入一些字符而不是数字，*******
将永远循环。快速浏览书籍没有向我展示任何解决方案，而是输入一些
字符串然后解析。我想要的只是复活cin来再次转弯，是否可能？
是的，它是。
如果你输入例如。字符a，然后cin>> a认识到它不能使用这个字符来构造一个数字。转换停止
并且由于没有输入用于形成数字的可用字符输入
操作会做两件事：它会因错误而停止转换。它将
返回该输入流的字符以便稍后处理（可能是另一个>>操作的
）。因此，当循环在下一次翻转时，操作会一次又一次地看到同一个字符。
- >你需要摆脱那种输入。查找流成员函数ignore（）。
-
Karl Heinz Buchegger
kb ****** @ gascad.at
Anand写道：< blockquote class =post_quotes> if（！std :: cin）
{
std :: cout<<" Oouch，你没有听我说......我快死了.. .. \ n";
std :: cin.clear（）; ///我想再转一圈而不是永久循环
//你需要做同步
std :: cin.sync（）;
sync（）与问题无关。
OP需要摆脱错误的输入。 ignore（）这样做。
-
Karl Heinz Buchegger
kb ****** @ gascad.at
Hi All,
I just have found out (for myself) that the program:
//**************************************
#include <iostream>
int main()
{
int a=0;
while(true)
{
std::cout << "Input a NUMBER!!!\n" << std::endl;
std::cin>>a; /// Here I input "a" eg char
if(!std::cin)
{
std::cout<<"Oouch, you have not listend me... I''m dying....\n";
std::cin.clear(); /// I want just to make another turn and not
cycle for eternity
}
std::cout<<a<<"\n";
}
return 0;
}
//**************************************
cycles forever if i input some char instead of numbers. Fast look throw
books have not showed me any solution for this but inputing into some
string and then parsing. All i want is just resurrect cin to make
another turn, is it possible?
--
float_dublin
float_dublin wrote:Hi All,
I just have found out (for myself) that the program:
//**************************************
#include <iostream>
int main()
{
int a=0;
while(true)
{
std::cout << "Input a NUMBER!!!\n" << std::endl;
std::cin>>a; /// Here I input "a" eg char
if(!std::cin)
{
std::cout<<"Oouch, you have not listend me... I''m dying....\n";
std::cin.clear(); /// I want just to make another turn and not
cycle for eternity // you need to do a sync
std::cin.sync(); }
std::cout<<a<<"\n";
}
return 0;
}
//**************************************
cycles forever if i input some char instead of numbers. Fast look throw
books have not showed me any solution for this but inputing into some
string and then parsing. All i want is just resurrect cin to make
another turn, is it possible?
--
float_dublin
float_dublin wrote:
Hi All,
I just have found out (for myself) that the program:
//**************************************
#include <iostream>
int main()
{
int a=0;
while(true)
{
std::cout << "Input a NUMBER!!!\n" << std::endl;
std::cin>>a; /// Here I input "a" eg char
if(!std::cin)
{
std::cout<<"Oouch, you have not listend me... I''m dying....\n";
std::cin.clear(); /// I want just to make another turn and not
cycle for eternity
}
std::cout<<a<<"\n";
}
return 0;
}
//**************************************
cycles forever if i input some char instead of numbers. Fast look throw
books have not showed me any solution for this but inputing into some
string and then parsing. All i want is just resurrect cin to make
another turn, is it possible?
Yes, it is.
If you input eg. the character a, then cin >> a recognizes that it can''t
use this character for constructing a number. This the conversion stops
and since no usable character for forming a number was entered the input
operation does 2 things: it stops the conversion with an error. it feeds
back that character to the input stream to be processed later (probably
by another >> operation). So when the loop turns over the next time, theoperation sees that very same character again and again and again.
-> You need to get rid of that input. Look up stream member function ignore().
--
Karl Heinz Buchegger
kb******@gascad.at
Anand wrote:if(!std::cin)
{
std::cout<<"Oouch, you have not listend me... I''m dying....\n";
std::cin.clear(); /// I want just to make another turn and not
cycle for eternity
// you need to do a sync
std::cin.sync();
sync() has nothing to do with the problem.
The OP needs to get rid of the erronous input. ignore() does this.
--
Karl Heinz Buchegger
kb******@gascad.at
这篇关于复活的cin的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
