I`m trying to use a QVector with a custom object named RoutineItem.
But this error is given:
C:\Qt\5.2.1\mingw48_32\include\QtCore\qvector.h:265: error: no matching function for call to 'RoutineItem::RoutineItem()'
This is the RoutineItem constructor:
RoutineItem(QString Name,int Position,int Time,bool hasCountdown = false,bool fastNext = false);
If I remove all the constructor arguments I no longer get that error. How can I use QVector with a custom object that has arguments?
The problem is that QVector requires that the element has a default constructor (that is the error message about). You can define one in your class. For example:
class RoutineItem {
RoutineItem(QString Name, int Position,
int Time, bool hasCountdown = false,
bool fastNext = false);
RoutineItem();
[..]
};
Alternatively, you can let all arguments have a default values:
class RoutineItem {
RoutineItem(QString Name = QString(), int Position = 0,
int Time = 0, bool hasCountdown = false,
bool fastNext = false);
[..]
};
Alternatively, you can construct a default value of RoutineItem and initialize all vector items by it:
RoutineItem item("Item", 0, 0);
// Create a vector of 10 elements and initialize them with `item` value
QVector<RoutineItem> vector(10, item);
Provide the non-default arguments in QVector constructor
Example: following creates 10 RoutineItem elements with same Name, Position, Time
QVector<RoutineItem> foo(10, RoutineItem("name", 123, 100 ));
^ ^ ^
| | |
+-----+-----+-----Provide arguments
If you're willing to use C++11 and std::vector, there's no more requirement for default-constructability:
void test()
{
class C {
public:
explicit C(int) {}
};
std::vector<C> v;
v.push_back(C(1));
v.push_back(C(2));
}
This code won't work pre-C++11, and it won't work with QVector.
std::listdoesn't even require copy-constructible items if you can stick to theemplace_instead ofpush_methods.