c++ - Stop Code instead of break with a Error Message -


here code great website want quite (searching in vector of class objects addressing class objects).

#include <iostream> #include <vector> #include <functional> #include <algorithm>    using namespacestd;  class class1 { private:     int id;     double value;  public:     class1(int i, double v) :id(i), value(v){ }     int getid()const { return id; }     double getvalue() const { return value; } };  class hasidentifier :public unary_function<class1, bool> { public:     hasidentifier(int id) : m_id(id) { }     bool operator()(const class1& c)const     {         return (c.getid() == m_id);     } private:     int m_id; };   class class2 { private:     vector <class1> objects; public:     class2()     {         objects.push_back(class1(1, 100.0));         objects.push_back(class1(2, 100.0));         objects.push_back(class1(3, 100.0));     }      double getvalueofid(int id)     {         vector<class1>::iterator itelem = find_if(objects.begin(), objects.end(),  hasidentifier(id));         return itelem->getvalue();     } };  int main() {      class2 c;      int id = 4;      cout << id << " " << c.getvalueofid(id);     cin.get();     return 0; }

it works whenenver put "int id ">3 crashes because object has size 3. got this, there possibility warned when happen not crash im able correct somehow in code warn message?

you should check returned iterator validness , throw , exception (or report error other way) if invalid:

if (itelem == objects.end())     throw myverycoolexception("woops wrong id");

dont forget set global exception handler (toplevel catch), otherwise application still crash if exception uncaught.


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