Mixing
Failcheck message gets repeated for the same amount of invalid characters contained inside the wcin
I am currently getting back to programming and started with a simple second degree equation calculator. I'm getting an unexpected behavior which I have no idea why is happening.
I have a while that checks if the values of a, b and c are numerical, with a fail message if they are not. But the fail message gets repeated for the same amount of invalid characters inside the unacceptable input.
Here is the code:
wcout << "Insert a value for a: n";
wcin >> a;
while (wcin.fail())
{
wcin.clear();
wcin.ignore();
wcout << L"Please insert a numerical value.n";
wcin >> a;
}
Example of the problem described.
If someone knows what is going on, I'd appreciate the help
EDIT: I am using wcout and wcin because of UNICODE characters such as letters with accent marks and greek symbols. I don't know if this problem could be related to this, but often I get the error saying "wcin/wcout is ambiguous"
c++ validation input calculator
asked Nov 20 '18 at 15:45
IgnisIgnis
84
add a comment |
I am currently getting back to programming and started with a simple second degree equation calculator. I'm getting an unexpected behavior which I have no idea why is happening.
I have a while that checks if the values of a, b and c are numerical, with a fail message if they are not. But the fail message gets repeated for the same amount of invalid characters inside the unacceptable input.
Here is the code:
wcout << "Insert a value for a: n";
wcin >> a;
while (wcin.fail())
{
wcin.clear();
wcin.ignore();
wcout << L"Please insert a numerical value.n";
wcin >> a;
}
Example of the problem described.
If someone knows what is going on, I'd appreciate the help
EDIT: I am using wcout and wcin because of UNICODE characters such as letters with accent marks and greek symbols. I don't know if this problem could be related to this, but often I get the error saying "wcin/wcout is ambiguous"
c++ validation input calculator
asked Nov 20 '18 at 15:45
IgnisIgnis
84
add a comment |
I am currently getting back to programming and started with a simple second degree equation calculator. I'm getting an unexpected behavior which I have no idea why is happening.
I have a while that checks if the values of a, b and c are numerical, with a fail message if they are not. But the fail message gets repeated for the same amount of invalid characters inside the unacceptable input.
Here is the code:
wcout << "Insert a value for a: n";
wcin >> a;
while (wcin.fail())
{
wcin.clear();
wcin.ignore();
wcout << L"Please insert a numerical value.n";
wcin >> a;
}
Example of the problem described.
If someone knows what is going on, I'd appreciate the help
EDIT: I am using wcout and wcin because of UNICODE characters such as letters with accent marks and greek symbols. I don't know if this problem could be related to this, but often I get the error saying "wcin/wcout is ambiguous"
c++ validation input calculator
asked Nov 20 '18 at 15:45
IgnisIgnis
84
I am currently getting back to programming and started with a simple second degree equation calculator. I'm getting an unexpected behavior which I have no idea why is happening.
I have a while that checks if the values of a, b and c are numerical, with a fail message if they are not. But the fail message gets repeated for the same amount of invalid characters inside the unacceptable input.
Here is the code:
wcout << "Insert a value for a: n";
wcin >> a;
while (wcin.fail())
{
wcin.clear();
wcin.ignore();
wcout << L"Please insert a numerical value.n";
wcin >> a;
}
Example of the problem described.
If someone knows what is going on, I'd appreciate the help
EDIT: I am using wcout and wcin because of UNICODE characters such as letters with accent marks and greek symbols. I don't know if this problem could be related to this, but often I get the error saying "wcin/wcout is ambiguous"
c++ validation input calculator
c++ validation input calculator
asked Nov 20 '18 at 15:45
IgnisIgnis
84
asked Nov 20 '18 at 15:45
IgnisIgnis
84
edited Nov 20 '18 at 15:54
Ignis
asked Nov 20 '18 at 15:45
IgnisIgnis
84
asked Nov 20 '18 at 15:45
IgnisIgnis
84
asked Nov 20 '18 at 15:45
IgnisIgnis
84
84
add a comment |
add a comment |
1 Answer
1
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oldest
votes
While wcin.clear() only sets the stream error state flags, the input stream must be reset, for example by wcin.ignore(...)
If you use wcin.ignore() it will use default parameters (see here): one character or the end of file condition.
Entering "aaa" will only extract an 'a', the rest remain in the input, which will be re-tested again in the next while-loop.
Entering from the console usually implies the 'Enter' key, whose character is 'n'. This is the delimiter we need to use to reset the input:
wcin.ignore(100, 'n');
Notice I've written 100. If you want to discard any number of characters then you need:
#include <limits>
....
wcin.ignore(std::numeric_limits<std::streamsize>::max(), 'n');
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
While wcin.clear() only sets the stream error state flags, the input stream must be reset, for example by wcin.ignore(...)
If you use wcin.ignore() it will use default parameters (see here): one character or the end of file condition.
Entering "aaa" will only extract an 'a', the rest remain in the input, which will be re-tested again in the next while-loop.
Entering from the console usually implies the 'Enter' key, whose character is 'n'. This is the delimiter we need to use to reset the input:
wcin.ignore(100, 'n');
Notice I've written 100. If you want to discard any number of characters then you need:
#include <limits>
....
wcin.ignore(std::numeric_limits<std::streamsize>::max(), 'n');
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
add a comment |
While wcin.clear() only sets the stream error state flags, the input stream must be reset, for example by wcin.ignore(...)
If you use wcin.ignore() it will use default parameters (see here): one character or the end of file condition.
Entering "aaa" will only extract an 'a', the rest remain in the input, which will be re-tested again in the next while-loop.
Entering from the console usually implies the 'Enter' key, whose character is 'n'. This is the delimiter we need to use to reset the input:
wcin.ignore(100, 'n');
Notice I've written 100. If you want to discard any number of characters then you need:
#include <limits>
....
wcin.ignore(std::numeric_limits<std::streamsize>::max(), 'n');
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
add a comment |
While wcin.clear() only sets the stream error state flags, the input stream must be reset, for example by wcin.ignore(...)
If you use wcin.ignore() it will use default parameters (see here): one character or the end of file condition.
Entering "aaa" will only extract an 'a', the rest remain in the input, which will be re-tested again in the next while-loop.
Entering from the console usually implies the 'Enter' key, whose character is 'n'. This is the delimiter we need to use to reset the input:
wcin.ignore(100, 'n');
Notice I've written 100. If you want to discard any number of characters then you need:
#include <limits>
....
wcin.ignore(std::numeric_limits<std::streamsize>::max(), 'n');
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
While wcin.clear() only sets the stream error state flags, the input stream must be reset, for example by wcin.ignore(...)
If you use wcin.ignore() it will use default parameters (see here): one character or the end of file condition.
Entering "aaa" will only extract an 'a', the rest remain in the input, which will be re-tested again in the next while-loop.
Entering from the console usually implies the 'Enter' key, whose character is 'n'. This is the delimiter we need to use to reset the input:
wcin.ignore(100, 'n');
Notice I've written 100. If you want to discard any number of characters then you need:
#include <limits>
....
wcin.ignore(std::numeric_limits<std::streamsize>::max(), 'n');
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
answered Nov 20 '18 at 18:15
Ripi2Ripi2
4,2831825
4,2831825
add a comment |
add a comment |
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