如何脱离io的死循环？

[jingyueid]

unsigned int i = 0;

do {
cin >> i;
cout << i;
} while ( i == 0 );

i为一个非零值，但只要输入是不合法的就进入死循环。

要怎么处理？才能保证i会接受一个合法的数字（不等于0），并且如果用户的输入不合法，会要求用户重新输入？

[jingyueid]

在线等，立结！

[nasi00]

我的vc6并没有死循环阿，是不是得接着输入让你觉得像是死了？你看看键盘还能用么？

看到提示的话就重新输入：

#include <iostream>
using namespace std;

int main()
{
unsigned int i = 0;

do {
cout << "input:";
cin >> i;
if(!i)
cout << "input error." << endl;
else
cout << i << endl;
} while (i == 0);

return 0;

}

[jingyueid]

我在vc2003, gcc下都是死循环。

vc6是不是会自动将标准输入的缓冲区给清空了？？

[zhouhuahai]

#include <iostream>
using namespace std;

int main()
{
unsigned int i = 0;

do {
cin.clear();
cin.ignore();
cout << "input:";
cin >> i;
if(!i)
cout << "input error." << endl;
else
cout << i << endl;
} while (i == 0);

return 0;

}

在while里面加入
cin.clear();
cin.ignore();就不会死循环了.

[jingyueid]

非常感谢！

ios::clear
void clear( int nState = 0 );

Parameter

nState

If 0, all error bits are cleared; otherwise bits are set according to the following masks (ios enumerators) that can be combined using the bitwise OR ( | ) operator. The nState parameter must have one of the following values:

ios::goodbit No error condition (no bits set).


ios::eofbit End of file reached.


ios::failbit A possibly recoverable formatting or conversion error.


ios::badbit A severe I/O error.
Remarks

Sets or clears the error-state flags. The rdstate function can be used to read the current error state.




istream::ignore
istream& ignore( int nCount = 1, int delim = EOF );

Parameters

nCount

The maximum number of characters to extract.

delim

The delimiter character (defaults to EOF).

Remarks

Extracts and discards up to nCount characters. Extraction stops if the delimiter delim is extracted or the end of file is reached. If delim = EOF (the default), then only the end of file condition causes termination. The delimiter character is extracted.

istream Overview | Input Stream Classes