declaration

问题 class forums : public master{ public: forums() : next(0),prev(0) {} } Please Explain what exactly does the functions next(0) and prev(0) are meant? What does seperation of function with a comma (,) indicates? what's the effect of empty braces {}, next to these functions? I am a beginner in C++, and trying to figure out what does this means, or intended use for these way of writing function? like is it specially meant for overriding? 回答1: Short answer That is a constructor with an empty body,

问题 I am trying to migrate the next code from Objetive-C to Swift: NSArray *voices = [AVSpeechSynthesisVoice speechVoices]; NSArray *languages = [voices valueForKey:@"language"]; NSLocale *currentLocale = [NSLocale autoupdatingCurrentLocale]; NSMutableDictionary *dictionary = [NSMutableDictionary dictionary]; for (NSString *code in languages) { dictionary[code] = [currentLocale displayNameForKey:NSLocaleIdentifier value:code]; } And I did the following: var voices:NSArray = AVSpeechSynthesisVoice

问题 I'm using Twilio.js library on my application (not Twilio Node) and there's no module nor typings for this library available. There's only a Twilio global variable available that one can use. The simplest ambient declaration one can have to avoid errors in the IDE is this: declare const Twilio: any; But I want to go a little bit further and for that I've been reading TypeScript handbook and few other resources. I've taken especially attention to this link. And here's what I have so far:

问题 I am looking at a library on github which has the following in one of the header files: class Util { public: static void log( const string& message ); static void log( const char* message ); template<typename T> static inline string toString(T t) { stringstream s; s << t; return s.str(); } }; and the following in the source file: void Util::log( const string& message ) { const string& logMessage = "[cppWebSockets] " + message; syslog( LOG_WARNING, "%s", logMessage.c_str( ) ); } void Util::log

问题 I've started learning C and have reached the point of enums. An enum is basically a preferred alternative to DEFINE / const int , correct? What's the difference between these two declarations? #include <stdio.h> // method 1 enum days { Monday, Tuesday }; int main() { // method 1 enum days today; enum days tomorrow; today = Monday; tomorrow = Tuesday; if (today < tomorrow) printf("yes\n"); // method 2 enum {Monday, Tuesday} days; days = Tuesday; printf("%d\n", days); return 0; } 回答1: An

问题 I'm writing a demo program from an educational book made to teach "C" for Unix and Windows. However, sometimes I come across code that, when typed exactly, does not want to work. Eg. #include <stdio.h> int main() { /*This next line is the error */ int num = 2, bool = 0; if ( (num==2) && (!bool) ) { printf("The first test is untrue\n"); } else if( (num==2) && (!bool) ) { printf("The second test is true\n"); } else if( (num==2) && (bool==0) ) { printf("The third test is true - but unreached\n")

问题 I've been looking for some clarification for the usage of the using-declarations in header files (I was searching around but couldn't quite get the answer I'm looking for). What I my research concluded so far is, using them in the non-global scope is ok, while namespace directives are bad. That I understood (At least I hope so :)). So in my example I use shared_ptr s, but I need to support older compilers that do not have them in the std:: namespace but in std::tr1:: for example. Since every

问题 I have come to know from book that for declaring a structure variable it is necessary a preceding struct keyword, but without that preceding struct in my Bloodshed\DevC++ compiler variable can be declared without any error like following, struct stype { int ival; float fval; double dval; }; and in main, stype s; s.ival=10;s.dval=23.23;s.fval=233.23; printf("%d %f %lf\n",s.ival,s.fval,s.dval); This correctly prints what should be printed. Is there any modification behind using this struct

问题 What is the difference between the code snippets labeled "version 1" and "version 2" in the following code section: int main() { using namespace std; typedef istream_iterator<int> input; // version 1) //vector<int> v(input(cin), input()); // version 2) input endofinput; vector<int> v(input(cin), endofinput); } As far as I understand "version 1" is treated as function declaration. But I don't understand why nor what the arguments of the resulting function v with return type vector<int> are.

问题 Z3 2.x had the feature (well, probably rather the bug) that symbol declarations were not popped away, e.g. the following code is accepted by Z3 2.x: (push) (declare-fun x () Int) ; Assumptions made in this scope will be popped correctly (pop) (assert (= x x)) Z3 3.x no longer accepts this code ("unknown constant"). Is there a way to restore the old behaviour? Or another way how one could declare symbols inside scopes such that the declaration (and only the declaration, not the assumptions) is