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Mac Forum / Programming / Mac Programming / March 2008How can i get an integer from a string using C++?
If I have a string such as "1.0" as a std::string, how can I convert that into a float or integer? > If I have a string such as "1.0" as a std::string, how can I convert > that into a float or integer? Wrap the string in a istringstream, and do normal steam i/o on it. Example: #include <iostream> #include <sstream> int main (int argc, char * const argv[]) { std::string s("3.14159"); float f; std::istringstream is(s); is >> f; std::cout << f << "\n"; return 0; } >> If I have a string such as "1.0" as a std::string, how can I convert >> that into a float or integer? [quoted text clipped - 14 lines] > return 0; > } Thanks, I got it. > >> If I have a string such as "1.0" as a std::string, how can I convert > >> that into a float or integer? [quoted text clipped - 15 lines] > > } > Thanks, I got it. The silly way to do it is: extract a C string from the C++ string, then you could use a C way of doing it like atof() or sscanf(), or you can get even sillier: convert the C string to an NSString, wrap that in an NSScanner, and have it parse the string. #include <iostream> #include <Cocoa/Cocoa.h> int main (int argc, char * const argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; std::string s("3.14159"); const char *sc = s.c_str(); NSString *nsc = [NSString stringWithUTF8String:sc]; NSScanner *scanner = [NSScanner scannerWithString:nsc]; float f; if([scanner scanFloat:&f]){ std::cout << f << "\n"; } [pool release]; return 0; } >>>> If I have a string such as "1.0" as a std::string, how can I convert >>>> that into a float or integer? [quoted text clipped - 37 lines] > return 0; > } Thanks, but I needed to use a pure C++ solution. > Thanks, but I needed to use a pure C++ solution. If you are using boost, then #include <boost/lexical_cast.hpp> string s; int x = lexical_cast<int>(s); and similarly for a float. Ben  SignatureIf this message helped you, consider buying an item from my wish list: <http://artins.org/ben/wishlist> > NSString *nsc = [NSString stringWithUTF8String:sc]; > NSScanner *scanner = [NSScanner scannerWithString:nsc]; Once you have an NSString, you can just send it a -floatValue message. No need to instantiate an NSScanner. -jcr |
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