QList<struct>

[Axsis]

Hi
I am working in winХР, qt.4.3.3.
First will show my code:

#include <QVector>
#include <QList>
#include <QString>
#include <QImage>
//#include <list.h>
//#include <vector.h>
typedef struct{
		unsigned int x;
		unsigned int y;
		unsigned int z;
		unsigned short int A1;
		unsigned short int A2;
		unsigned short int A3;
		unsigned short int A4;
		unsigned short int A[1024];
	} dataPoint;
typedef struct{
		QVector<dataPoint>		dataVector;
		QImage				      preview;
		QString					author;
		QString					date;
		QString					time;
	} dataScan;
class DataStorage
{
	//Q_OBJECT
public:
	DataStorage();
	QVector<dataPoint>		      point;
	QList<dataScan>				dataContainer;
	QList<dataScan>::iterator	     dataContainerIterator;
};

#include <QVector>
#include <QList>
#include <QString>
#include <QImage>
//#include <list.h>
//#include <vector.h>
typedef struct{
		unsigned int x;
		unsigned int y;
		unsigned int z;
		unsigned short int A1;
		unsigned short int A2;
		unsigned short int A3;
		unsigned short int A4;
		unsigned short int A[1024];
	} dataPoint;
typedef struct{
		QVector<dataPoint>		dataVector;
		QImage				      preview;
		QString					author;
		QString					date;
		QString					time;
	} dataScan;
class DataStorage
{
	//Q_OBJECT
public:
	DataStorage();
	QVector<dataPoint>		      point;
	QList<dataScan>				dataContainer;
	QList<dataScan>::iterator	     dataContainerIterator;
};

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I need to get access to elements of structure dataContainer and dataVector which is an element of dataContainer. I tried various ways, but at execution the program gives out errors like "QVector: index out of range". When I used classical C++ list and vector I receive RuntimeError.
Below some ways with which I tried to get access to the necessary elements of structures
are shown. But any of them does not work.

DataStorage::DataStorage()
{
    const int nPoints = 360;
	int q=0;
	dataContainerIterator = dataContainer.begin();
	for (int i=0;i<=nPoints;i++)
	{
		q = qAbs(qRound(100*sin(i*3.14/180)));
		dataContainerIterator->dataVector[i].x << i;
		dataContainerIterator->dataVector[i].x = i;
		dataContainerIterator->dataVector.at(i).x << 1;
	}
}

DataStorage::DataStorage()
{
    const int nPoints = 360;
	int q=0;
	dataContainerIterator = dataContainer.begin();
	for (int i=0;i<=nPoints;i++)
	{
		q = qAbs(qRound(100*sin(i*3.14/180)));
		dataContainerIterator->dataVector[i].x << i;
		dataContainerIterator->dataVector[i].x = i;
		dataContainerIterator->dataVector.at(i).x << 1;
	}
}

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Where is my mistake?

[wysota]

Did you allocate enough space in the vector? You can't add data to an empty vector using the index operator.

[Axsis]

Did you allocate enough space in the vector? You can't add data to an empty vector using the index operator.

No, I don't know how much memory can be neccessary. If I do as it is shown below I receive errer: class QVector<dataPoint>' has no member named 'x'.

dataContainerIterator->dataVector.x << i;

dataContainerIterator->dataVector.x << i;

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As far as I know there is no necessity to allocate memory before add a data.

[wysota]

As far as I know there is no necessity to allocate memory before add a data.

You are not adding data. You are assigning data.

[Axsis]

Ok. It's clear. But how I can allocate memory for dataVector? I mean that it is an element of structure not a usual vector.

Solved...

[wysota]

Use QVector::resize or QVector::push_back.

[Axsis]

Use QVector::resize or QVector::push_back.

I know about this functions but I dont know how to use it. I mean that I have QVector<struct> and I don't know how to call QVector::push_back if I want to add .x, then .y ...

[wysota]

QVector<MyStruct> vec;
MyStruct s;
s.x = 7;
s.y = 8;
vec.push_back(s);

QVector<MyStruct> vec;
MyStruct s;
s.x = 7;
s.y = 8;
vec.push_back(s);

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