String Finding Question

[Mike Copeland]

The C++ "find" functions seem more cumbersome than their C ancestors.
To me, string::find is more difficult to use than, say, strchr. For
example,

char *ptr = strchr("AEMT", 'A');
if(ptr != NULL) do_something_if_found;
else do_not_found;

Is there a simpler C++ way to code the following?

std::string valids = "AEMT";
size_t idx = valids.find('A');
if(idx != string::npos) do_something_if_found;
else do_not_found;

 

[Marcel Müller]

The C++ "find" functions seem more cumbersome than their C ancestors.
To me, string::find is more difficult to use than, say, strchr. For
example,

char *ptr = strchr("AEMT", 'A');
if(ptr != NULL) do_something_if_found;
else do_not_found;

Is there a simpler C++ way to code the following?

std::string valids = "AEMT";
size_t idx = valids.find('A');
if(idx != string::npos) do_something_if_found;
else do_not_found;

Where is the difference? Do you claim about the extra line for the
constant valids? You could eliminate it:
size_t idx = std::string("AEMT").find('A');

However, declaring valids as a static constant saves the allocations
needed for std::string constructor.


Marcel

 

[Mike Copeland]

Where is the difference? Do you claim about the extra line for the
constant valids? You could eliminate it:
size_t idx = std::string("AEMT").find('A');

However, declaring valids as a static constant saves the allocations
needed for std::string constructor.

Yes, I do find the extra line annoying, but your reply is the sort of
thing I was seeking: a shorthand way to scan a constant without all the
extraneous declaration, etc. Thank you. 8<}}

 

[Jorgen Grahn]

The C++ "find" functions seem more cumbersome than their C ancestors.
To me, string::find is more difficult to use than, say, strchr. For
example,

char *ptr = strchr("AEMT", 'A');
if(ptr != NULL) do_something_if_found;
else do_not_found;

Is there a simpler C++ way to code the following?

std::string valids = "AEMT";
size_t idx = valids.find('A');
if(idx != string::npos) do_something_if_found;
else do_not_found;

I prefer using std::find, since I'm more familiar with iterators than
that funny string-specific stuff:

std::string valids = "AEMT";
if(std::find(valids.begin(), valids.end(), 'A') != valids.end()) {
do_something_if_found;
}
else {
do_not_found;
}

If I do this a lot in a source file, I'll probably write a

bool contains(const string&, char);

helper function.

/Jorgen