C + + Learning Path: Priority queuing using templates (to prevent forgetting)

When our custom rules are stored in the priority queue, the compiler does not know how to sort

such as: priority_queue<person> This code is not compiled, we need to manually write a comparison rule

Priority_queue<person, comp> can

The code is as follows

1#include <iostream>2#include <string>3#include <vector>4#include <queue>5#include <fstream>6#include <stdexcept>7 using namespacestd;8 9 structscoreTen { One     intid_; A     stringname_; -     intscore_; -  theScore (intIdConst string&name,intscore) - : id_ (ID), name_ (name), Score_ (score) -     { } - }; +  - classComp + { A  Public: at     BOOL operator() (ConstScore &s1,ConstScore &S2) -     { -         if(S1.score_! =s2.score_) -             returnS1.score_ <s2.score_; -         if(S1.name_! =s2.name_) -             returnS1.name_ >s2.name_; in         returnS1.id_ >s2.id_; -     }  to }; +  -typedef priority_queue<score, Vector<score>, comp>scorelist; the  * voidReadFile (Const string&filename, Scorelist &scores); $ voidPrintscorelist (Scorelist &scores);Panax Notoginseng  - intMainintargcChar Const*argv[]) the { + Scorelist scores; A  theReadFile ("Score.txt", scores); + printscorelist (scores); - } $  $ voidReadFile (Const string&filename, Scorelist &scores) - { -Ifstreaminch(Filename.c_str ()); the     if(!inch) -         ThrowRuntime_error ("File open failed");Wuyi  the     stringLine ; -      while(Getline (inch, line)) Wu     { -         intID; About         Charname[ -] = {0}; $         intscore; -SSCANF (Line.c_str (),"%d%s%d", &id, Name, &score); - Scores.push (Score (ID, name, score)); -     } A  +     inch. Close (); the } -  $ voidPrintscorelist (Scorelist &scores) the { the      while(!scores.empty ()) the     { theScore S =scores.top (); - Scores.pop (); incout <<"id ="<< s.id_ <<"name ="<< s.name_ <<"score ="<< s.score_ <<Endl; the     } the}

The above example is a very simple sort of transcript. Simply write a collation class and reload the () function call symbol on the sorting class.

This code is used to forget when to review

C + + Learning Path: Priority queuing using templates (to prevent forgetting)