c++ - 在对象内的数组中设置值

Question

我遇到了对象中对象数组的问题:

我有一个带有对象数组的类:

class element
{
public:
element() {};
LinePiece* arrayLP; 

我在数组中有一个类:

class LinePiece
{
public:
LinePiece() {};

AnsiString Type;
int ElementNr;
int Status;
int X, Y;

所以在 Element 对象中我有一个 LinePiece 数组。奇怪的是，当我填写 ElementArray[1].LPArray[0];它被下一个对象覆盖 (ElementArray[2].LPArray[0];

我用下面的代码填充它:

String FileBuffer;
String Regel;
String Code;

element* GetElementInfo()
{
//alle onderdelen van een Elementobject
String OrderNumber;             //ON
String OrderBrand;              //MO
String ElementNumber;           //SN
String ElementMarking;          //RS
String ReinforcementPattern;    //OW
String CalculationNumber;       //CN
String ElementLength;           //LE
String ElementWidth;            //WD
String ElementBeginX;           //BP
String ConcreteThickness;       //TH
String Isulation;               //IH
String Weight;                  //NW

element *ElementArray = new element[100];
LinePiece *LPArray = new LinePiece[100];
bool firstElement = true;
int Index =0;
int LPIndex = 0;

for(int i = 1; i <= FileBuffer.Length(); i++)
{
    if(FileBuffer[i] != 0)
    {
        if(FileBuffer[i] != IntToStr('\r'))  //controleren of je op einde regel zit, zoniet vul de string "regel" aan
        {
            if(FileBuffer[i] != IntToStr('\r') && FileBuffer[i] != IntToStr('\n'))
            {
                Regel = Regel + FileBuffer[i];
            }
        }
        else //kijken wat er op de regel staat
        {
            Code = Regel.SubString(0,2);

            if(Code == "ON") //Ordernummer
            {
                OrderNumber = Regel.SubString(4, (Regel.Length() -3));
                Regel = "";
            }
            if(Code =="MO")  //Ordermerk
            {
                 OrderBrand = Regel.SubString(4, (Regel.Length() -3));
                 Regel = "";
            }

            if(Code =="SN")  //Element nummer
            {
                ElementNumber = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }

            if(Code =="RS") //Element marking
            {
                ElementMarking = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }

            if(Code =="CN") //Calculatienummer
            {
                CalculationNumber = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }

            if(Code == "LE") //Element lengte
            {
                ElementLength = Regel.SubString(4,(Regel.Length()-3));
                Regel = "";
            }

            if(Code == "WD") //element breedte
            {
                ElementWidth = Regel.SubString(4,(Regel.Length()-3));
                Regel = "";
            }

            if(Code == "BP") //beginpunt X
            {
                ElementBeginX = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }
            if (Code == "OW") //Wapeningspatroon
            {
                ReinforcementPattern = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }
            if(Code == "TH")  //Beton dikte
            {
                ConcreteThickness = Regel.SubString(4,(Regel.Length()-3));
                Regel = "";
            }

            if(Code == "IH") //isolatie dikte
            {
                Isulation = Regel.SubString(4,(Regel.Length()-3));
                Regel = "";
            }

            if(Code == "NW")  //Gewicht
            {
                Weight = Regel.SubString(4, (Regel.Length()-3));
                Regel = "";
            }

            if(Code == "CO") //Contour
            {
                String geheleRegel = Regel.SubString(4, (Regel.Length() -3));

                int EleNr = 0;
                int Status = 0;
                //geheleRegel doormidden hakken voor x en y waardes.
                String X = geheleRegel.SubString(0, (geheleRegel.Length() /2));
                String Y = geheleRegel.SubString(geheleRegel.Length()/2 +1, geheleRegel.Length());

                LinePiece lpObject(Code, EleNr, Status, StrToInt(X), StrToInt(Y));
                LPArray[LPIndex] = lpObject;
                LPIndex++;
                Regel = "";
            }


            if(Code == "*" && firstElement == false) //Nieuw element
            {
                if(OrderNumber == "")
                {
                    OrderNumber =="-";
                }

                if(OrderBrand == "")
                {
                    OrderBrand = "-";
                }

                if(ElementNumber == "")
                {
                    ElementNumber = "-";
                }

                if(ElementMarking == "")
                {
                    ElementMarking = "-";
                }

                if (ReinforcementPattern == "")
                {
                    ReinforcementPattern = "-";
                }

                if (CalculationNumber == "")
                {
                    CalculationNumber = "-";
                }

                if(ElementLength == "")
                {
                    ElementLength = 0;
                }

                if(ElementWidth == "")
                {
                    ElementWidth = 0;
                }

                if(ElementBeginX == "")
                {
                    ElementBeginX = 0;
                }

                if(ConcreteThickness == "")
                {
                    ConcreteThickness = 0;
                }

                if(Isulation == "")
                {
                    Isulation = 0;
                }

                if(Weight == "")
                {
                    Weight = 0;
                }

                element ElementObject(OrderNumber, OrderBrand, ElementNumber, ElementMarking,
                ReinforcementPattern, CalculationNumber, StrToInt(ElementLength), StrToInt(ElementWidth),
                StrToInt(ElementBeginX), StrToInt(ConcreteThickness),StrToInt(Isulation),
                Weight, LPArray);

                ElementArray[Index] = ElementObject;
                LPIndex = 0;    /resetting LPIndex
                Index++;
            }
            else  
            {
                Regel="";
            }

            if (Code == "*")
            {
                 firstElement = false;
            }
        }

    }
}
return ElementArray;
}

所以出于某种原因，它不会生成“X”个不同的 LPArray，而是用最后一个覆盖所有的 LParray。我该如何解决这个问题？

Answer 1

您的初始化代码应该如下所示:

element *ElementArray = new element[100];
for ( int n = 0; n < 100; ++n )
  ElementArray[n].arrayLP = new LinePiece[100];

所以你描述的行为可能是由于未定义的行为造成的

你似乎没有在任何地方删除你分配的数组 - 这会导致内存泄漏。此外，如果您想要数组而不是 vector ，那么您必须遵守三原则(添加复制构造函数/运算符和析构函数)。