how to check a string whether it is

[zjffdu]

I know in .net it is easy, but in C++
how can I check a string whether it is composed by backspace,\t,\n?
Is there function can i call in the standard?

thanks for any hint

[Jim Langston]

"zjffdu" <zj****@gmail.com> wrote in message
news:11*********************@i40g2000cwc.googlegro ups.com...

I know in .net it is easy, but in C++
how can I check a string whether it is composed by backspace,\t,\n?
Is there function can i call in the standard?

thanks for any hint

Not exactly sure what you're asking for. But std::string.find_first_of()
might be what you want. "Whether it is composed by..." Is it totally? Or
included? Totally would be a simple == as in if ( MyString == "\t" ) has
within you could use if ( MyString.find_first_of("\t") != std::npos );

[zjffdu]

thanks
I mean how to judge a string whether there is no any other character
besides backspace,\t,and \n

[Dietmar Kuehl]

zjffdu wrote:

I mean how to judge a string whether there is no any other character
besides backspace,\t,and \n

if (str.find_first_not_of("\t\n\b") == str.npos)
std::cout << "the string contains nothing interesting\n";
--
<mailto:di***********@yahoo.com> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence

[Diego Martins]

http://www.cppreference.com/cppstring/index.html

[Tomás]

zjffdu posted:

I know in .net it is easy, but in C++
how can I check a string whether it is composed by backspace,\t,\n?
Is there function can i call in the standard?

thanks for any hint

Here's an elementary way to test if either character is present:

bool EitherPresent( const char* p )
{
for( ; ; ++p )
{
switch ( *p )
{
case '\t':
case '\n':
{
return true;
}

case 0:
{
return false;
}
}
}
}
-Tomás

[Tomás]

zjffdu posted:

thanks
I mean how to judge a string whether there is no any other character
besides backspace,\t,and \n

Simple again.

bool AnythingIntelligible( const char* p )
{
for( ; ; ++p )
{
switch ( *p )
{
case '\t':
case '\n':

break;

case 0:
{
return false;
}

default:

return true;
}
}
}

[Dietmar Kuehl]

Diego Martins wrote:

http://www.cppreference.com/cppstring/index.html

Er, I think I know the standard C++ library quite well. Did I goof?
.... and, if so, where?
--
<mailto:di***********@yahoo.com> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence

[Ben Pope]

Diego Martins wrote:

http://www.cppreference.com/cppstring/index.html

Do you have a point?

I'm pretty sure you're not just randomly pasting links into messages but
it would be good to quote some context from the post to which you are
responding, and also adding some words to describe the point of
providing the link.

Ben Pope
--
I'm not just a number. To many, I'm known as a string...

[Julián Albo]

Dietmar Kuehl wrote:

if (str.find_first_not_of("\t\n\b") == str.npos)
std::cout << "the string contains nothing interesting\n";

If the string contains a program in the whitespace language, it can be very
interesting.

--
Salu2