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我有一個程序使用迭代器來打印對象。指向每個對象的指針都存儲在一個向量中。當我嘗試通過取消引用迭代器來打印這些對象時，它只是打印內存位置。我相信它是因爲我有一個指向性的間接層，但是當我再次解除引用時，我得到了一個我一直無法追蹤的seg故障。任何人都可以找到問題嗎？解除迭代器到指針
int main(int argc, const char * argv[]){
ObjectFactory* objFact = readInput();
for (ObjectFactory::const_iterator p = objFact->begin(); p!=objFact->end(); ++p){
std::cout << *p << " ";
}
return 0;
}
ObjectFactory* readInput(){
std::vector<MyObject*> myObjects;
ObjectFactory* objFact = ObjectFactory::get_inst();
std::string input;
int years_passed;
std::cin >> years_passed;
std::cin >> input;
int age = 0;
float diameter = 0;
while (std::cin){
try{
if (input == "int"){
int value;
if (std::cin >> value){
if (value > 0){
age = value;
std::cin >> input;
}
else{
std::cin >> input;
throw negativeNumber("integer", value);
}
}
else{
std::cin.clear();
std::cin >> input;
throw missingValue("int", input);
}
}
else if (input == "float"){
float value;
if (std::cin >> value){
if (value > 0){
diameter = value;
std::cin >> input;
}
else{
std::cin >> input;
throw negativeNumber("float", value);
}
}
else{
std::cin.clear();
std::cin >> input;
throw missingValue("float", input);
}
}
else if (input == "string"){
std::string value;
std::cin >> value;
if (diameter == 0 || age == 0){
std::cin >> input;
throw incompleteObject(value);
}
try{
objFact->new_object(value, diameter, age);
}
catch (invalidAge ex){
ex.printMessage();
}
std::cin >> input;
}
else{
std::string tempInput = input;
std::cin >> input;
throw unrecognizedType(tempInput);
}
}
catch (unrecognizedType ex){
ex.printMessage();
}
catch (incompleteObject ex){
ex.printMessage();
}
catch (negativeNumber ex){
ex.printMessage();
}
catch (missingValue ex){
ex.printMessage();
}
}
return objFact;
}
class ObjectFactory {
public:
static ObjectFactory* get_inst();
MyObject* new_object(std::string name, float diameter, int age);
void time_passed(int year);
typedef std::vector<MyObject*>::const_iterator const_iterator;
const_iterator begin() const{return objects.begin();}
const_iterator end() const{return objects.end();}
protected:
ObjectFactory(){}
private:
static ObjectFactory* _instance;
std::vector<MyObject*> objects;
};
ObjectFactory* ObjectFactory::_instance=0;
ObjectFactory* ObjectFactory::get_inst(){
if (_instance ==0) {_instance = new ObjectFactory;}
return _instance;
}
//Create the correct object type based of the name
MyObject* ObjectFactory::new_object(std::string name, float diameter, int age){
if (toupper(name.at(0)) == 'C'){
objects.push_back((MyObject*)new Car(name, diameter, age));
return objects.at(objects.size()-1);
}
if (toupper(name.at(0)) == 'T'){
objects.push_back((MyObject*)new Tiger(name, diameter, age));
return objects.at(objects.size()-1);
}
objects.push_back((MyObject*)new Human(name, diameter, age));
return objects.at(objects.size()-1);
}
void ObjectFactory::time_passed(int year){
for (int i = 0; i < objects.size();i++){
objects[i]->year_passed(year);
if (objects[i]->get_age()>objects[i]->get_max_age()){
delete objects[i];
}
}
}
//Prints output for objecs of MyObject type
std::ostream& operator << (std::ostream& out, MyObject& obj)
{
out << "(" <<obj.get_type_name() << "," << obj.get_name() << "," << obj.get_diameter() << "," << obj.get_age() << ","<< obj.get_speed() << ")";
}
ObjectFactory* ObjectFactory::_instance=0;
ObjectFactory* ObjectFactory::get_inst(){
if (_instance ==0) {_instance = new ObjectFactory;}
return _instance;
}
//Create the correct object type based of the name
MyObject* ObjectFactory::new_object(std::string name, float diameter, int age){
if (toupper(name.at(0)) == 'C'){
objects.push_back((MyObject*)new Car(name, diameter, age));
return objects.at(objects.size()-1);
}
if (toupper(name.at(0)) == 'T'){
objects.push_back((MyObject*)new Tiger(name, diameter, age));
return objects.at(objects.size()-1);
}
objects.push_back((MyObject*)new Human(name, diameter, age));
return objects.at(objects.size()-1);
}
void ObjectFactory::time_passed(int year){
for (int i = 0; i < objects.size();i++){
objects[i]->year_passed(year);
if (objects[i]->get_age()>objects[i]->get_max_age()){
delete objects[i];
}
}
}
//Prints output for objecs of MyObject type
std::ostream& operator << (std::ostream& out, MyObject& obj)
{
out << "(" <<obj.get_type_name() << "," << obj.get_name() << "," << obj.get_diameter() << "," << obj.get_age() << ","<< obj.get_speed() << ")";
}
我並不包括爲MyObject或它的子類或我使用的，因爲它似乎不相關的錯誤結構的代碼，但讓我知道，如果你需要它。
std::cout << *(*p) << " ";
添加return聲明：
您似乎沒有ObjectFactory的'<<'運算符。 –
歡迎使用堆棧溢出。在編寫代碼時，獨立開發新功能非常重要*。你應該構造一個包含一個指向一個對象的指針（通過硬編碼構建，不需要運行時輸入），並在將它連接到I/O和其他所有對象之前完美工作。這個例子[既不完整也不小]（http://stackoverflow.com/help/mcve）。 – Beta
@Jonathan我的迭代器正在瀏覽ObjectFactory中名爲'objects'的數組。數組內部是MyObject指針。當我嘗試使用double取消引用時，從迭代器獲取MyObject指向MyObject本身的指針時，我收到了無法跟蹤的Seg故障。這就是爲什麼我沒有ObjectFactory的<<運算符。 – Evan