自学教程：C++ GetElem函数代码示例

bool GeneralMatrix::ExchangeRows(int iRow1,int iRow2) const{         int j;	ELEMTYPE temp;    if(this->nRow()<2||iRow1==iRow2)		return TRUE;    if(iRow1>=nRow()||iRow2>=nRow())        return FALSE;	    for(j=0;j<nCol();j++)	{                 temp = GetElem(iRow1,j);     GetElem(iRow1,j) = GetElem(iRow2,j);	 GetElem(iRow2,j) = temp;         	}return TRUE;   }

bool GeneralMatrix::MakeUnit() const{	if(nRow()!=nCol())		return FALSE;    Zero();	for (int i=0;i<nRow();i++)	    GetElem(i,i) = 1.0;return TRUE;	}

void unionL(SqList *La,SqList Lb){	ElemType e;	int La_len=ListLength(*La);	int Lb_len=ListLength(Lb);	for (int i=1;i<=Lb_len;i++)	{		GetElem(Lb,i,&e);		if (!LocateElem(*La,e))			ListInsert(La,++La_len,e);	}}

void Union(List &La, List Lb) {  // 算法2.1  // 将所有在线性表Lb中但不在La中的数据元素插入到La中  int La_len,Lb_len,i;  ElemType e;  La_len = ListLength(La);          // 求线性表的长度    Lb_len = ListLength(Lb);  for (i=1; i<=Lb_len; i++) {    GetElem(Lb, i, e);              // 取Lb中第i个数据元素赋给e    if (!LocateElem(La, e, equal))  // La中不存在和e相同的数据元素      ListInsert(La, ++La_len, e);  // 插入  }} // union

GeneralMatrix GeneralMatrix::GetColVector(int iCol) const{	int i;	GeneralMatrix Vector(nRow(),1,ERRORVAL);		if(iCol<0||iCol>nCol()-1||nRow()==0) return Vector;		for(i=0;i<nRow();i++)		Vector[i][0] = GetElem(i,iCol);	return Vector;}

/*************************************************************************** name       : FindElem* description: 查找元素* input      : pszElemName 待查找的元素名* output     : NA* return     : true - 成功，false - 失败* remark     : NA**************************************************************************/bool CXml::FindElem(const char *pszElemName){    CHECK_POINTER(pszElemName, false);    CHECK_POINTER(m_pXmlNode, false);    TiXmlNode* pTmpNode = m_pXmlNode;	// 将指针指向第一个元素	m_pXmlNode = m_pXmlNode->Parent()->FirstChild();    // 判断指针是否为空    CHECK_POINTER(m_pXmlNode, false);	m_pXmlElem = m_pXmlNode->ToElement();	// 增加一个变量检查控制情况	const char* pChkTmpNode = NULL;    while (((pChkTmpNode = GetElem()) != NULL) && (0 != strcmp(pszElemName, pChkTmpNode))) //lint !e838    {        if (NULL == m_pXmlNode->NextSibling())        {            break;        }        m_pXmlNode = m_pXmlNode->NextSibling();        m_pXmlElem = m_pXmlNode->ToElement();    }/*	while (0 != strcmp(pszElemName, GetElem()))    {        if (NULL == m_pXmlNode->PreviousSibling())        {            return false;        }        m_pXmlNode = m_pXmlNode->PreviousSibling();        m_pXmlElem = m_pXmlNode->ToElement();    }*/	const char* pNextTmpElem = this->GetElem();	CHECK_POINTER(pNextTmpElem, false);    if (0 == strcmp(pszElemName, pNextTmpElem))    {        return true;    }	// 如果找不到匹配节点，指针还原	m_pXmlNode = pTmpNode;	m_pXmlElem = m_pXmlNode->ToElement();	    return false;}

ELEMTYPE GeneralMatrix::Distance_E(GeneralMatrix& other) const{	     int i,j; 	ELEMTYPE result = ERRORVAL;	if(nRow()!=other.nRow()||nCol()!=other.nCol()) return result;    for(result=0,i=0;i<nRow();i++)		for(j=0;j<nCol();j++)		   result += pow(GetElem(i,j)-other[i][j],2);return sqrt(result);}

void GetPowerSet(int i, List A, List &B) {  // 算法6.15   // 线性表A表示集合A，线性表B表示幂集ρ(A)的一个元素。   // 局部量k为进入函数时表B的当前长度。   // 第一次调用本函数时，B为空表，i＝1。   ElemType x;   int k;   if (i > ListLength(A)) Output(B); // 输出当前B值，即ρ(A)的一个元素   else {       GetElem(A, i, x);        k = ListLength(B);      ListInsert(B, k+1, x);   GetPowerSet(i+1, A, B);      ListDelete(B, k+1, x);   GetPowerSet(i+1, A, B);   }} // GetPowerSet

// replace element of position index, so original element will toward backbool ListInsert(pListHeader plh, unsigned int index, pListNode pNode){    if(index > plh->ListSize)        ErrorFunc("Too much bigger index!/n", OUT_OF_SCOPE);    pListNode pRplcedNode = GetElem(plh, index);    pListNode pPriorNode = PriorElem(plh, pRplcedNode);    pNode->next = pPriorNode->next;    pPriorNode->next = pNode;    (plh->ListSize)++;    return true;}

void Constraint::LinkToElements() {	if (UsePenaltyFormulation()) //in penalty formulation, the SOS-DOF are hired from constrained elements	{		LinkToElementsPenalty();	}	else	{		for (int i = 1; i <= NE(); i++) //$ DR 2012-11-02: changed elements.Length() to NE(), because some constraints add element(2) = 0 for ground joints, NE() returns the correct value for these constraints 		{			GetElem(i).AddConstraint(this,i);		}	}}

void main(){	int *e;    Linklist L;	e=(int *)malloc(sizeof(int));    L=(Linklist)malloc(LEN);	Init_Link(L);	Show_Link(L);	Insert_List(L,17,2);    Show_Link(L);	GetElem(L,2,e);	printf("%d/n",*e);	free(e);}

/*====================================================================*	操作目的: 输出顺序表中的元素**	初始条件: 线性表L已存在**	操作结果: 输出了顺序表中的元素**	函数参数:*		SeqList *L	线性表L**	返回值:*		无======================================================================*/void Show_Elem(SeqList *L){	int i;	DataType e;	for(i = 0; i < L->length; i++)	{		if(GetElem(*L, i+1, &e) == false)		{			fprintf(stderr,"输出失败!/n");			exit(EXIT_FAILURE);		}		printf("%4d", e);	}}

void unionL(SqList *La, SqList Lb) /* union Lb to La */{				    int La_len, Lb_len, i;    ElemType e;    La_len = ListLength(*La);    Lb_len = ListLength(Lb);    for (i = 1; i <= Lb_len; ++i) {	GetElem(Lb, i, &e);	if (!LocateElem(*La, e))	    ListInsert(La, ++La_len, e);    }    }

void Union(SqList &La, SqList &Lb){//将所有在线性表Lb中但不在La中的数据元素插入到La中	ElemType e;	//int La_len, Lb_len;	int i;	//La_len = ListLength(La);	//Lb_len = ListLength(Lb);	for ( i = 1; i <= Lb.length; i++ )	{		GetElem(Lb, i, e);		if ( !LocateElem(La, e, equal) )			ListInsert(La, ++La.length, e);	}}

//#endif//********************************************************************//删除A中出现B的元素的函数实现void DelElem(SeqList *A,SeqList B){	int i,flag,pos;	DataType e;	for(i=0;i<B.length;i++)	{		flag=GetElem(B,i,&e);//依次把B中每个元素取出给		if(flag==1)		{			pos=LocateElem(*A,e);//在A中查找和B中取出的元素e相等的元素			if(pos>0)				DeleteList(A,pos,&e);//如果找到该元素，将其从A中删除		}	}}

int main() {	student s;	SqList L;	InitList_Sq(L);	s.score = 60; s.boy = true;	ListInsert_Sq(L, 1, s);	s.score = 70; s.boy = false;	ListInsert_Sq(L, 1, s);	s.score = 90; s.boy = false;	ListInsert_Sq(L, 2, s);	int n = Length(L);// int n = L.length;	for (int i = 1; i <= n; i++) {		GetElem(L, i, s);		std::cout << s.score << " " << s.boy << "/n";	}	ListDelete_Sq(L, 1, s);	std::cout << "删除的1号元素是："<<s.score << " " << s.boy << "/n";	n = Length(L);	for (int i = 1; i <= n; i++) {		GetElem(L, i, s);		std::cout << s.score << " " << s.boy << "/n";	}	double average_score = 0;	for (int i = 1; i <= n; i++) {		GetElem(L, i, s);		average_score += s.score;	}	average_score /= n;	std::cout << "平均分是" << average_score << "/n";	return 0;}

icSigBRDFFunction CIccStructBRDF::GetBRDFFunction() const{  CIccTag* pTag = GetElem(icSigTypeBrdfMember);  if (pTag)  {    if (pTag->GetType() == icSigSignatureType)    {      CIccTagSignature* pTagSig = dynamic_cast<CIccTagSignature*>(pTag);      if (pTagSig)        return  (icSigBRDFFunction)pTagSig->GetValue();    }  }  return (icSigBRDFFunction)icSigUnknownType;}

void union_func(SqList *La, SqList Lb){	int La_length, Lb_length, i;	ElemType e;	La_length = ListLength(*La);	Lb_length = ListLength(Lb);		for( i=1; i <= Lb_length; i++) {		GetElem(Lb, i, &e);		if( !LocateElem(*La, e) ) {			ListInsert(La, ++La_length, e);		}	}}

nsIContent*IDRefsIterator::NextElem(){  while (true) {    const nsDependentSubstring id = NextID();    if (id.IsEmpty())      break;    nsIContent* refContent = GetElem(id);    if (refContent)      return refContent;  }  return nsnull;}

void GeneralMatrix::Print(){	if (nRow()==0||nCol()==0)	{		return;	}	for (int i=0;i<nRow();i++)	{		for (int j=0;j<nCol();j++)		{			cout<<GetElem(i,j)<<" ";		}		cout<<endl;	}	cout<<endl;}

void Union1(Sqlist &La, Sqlist &Lb){    ElemType e;    int i;    int la_len, lb_len;    la_len = ListLength(La);    lb_len = ListLength(Lb);    for ( i = 1; i <= lb_len; i++ )    {        GetElem(Lb, i, e);        printf("e = %d/n", e);        if ( !LocateElem(La, e, equal) )            ListInsert_before(La, ++la_len, e);    }}

void unionL(sqList *La,sqList Lb){	int La_len,Lb_len,i;	ElemType e;		La_len =ListLength(*La);	Lb_len =ListLength(Lb);		for (i=1; i< Lb_len;i++) {		GetElem(Lb,i,&e);		if(!LocateElem(*La,e))		{			ListInsert(La,++La_len,e);		}	}}

//在双向循环链表的第i个位置插入元素e。插入成功返回1，否则返回0int InsertDList(DLinkList head,int i,char e){	DListNode *p,*s;	p=GetElem(head,i);	//查找链表中第i个结点	if(!p)		return 0;	s=(DListNode *)malloc(sizeof(DListNode));	if(!s)		return -1;	s->data=e;	//将s结点插入到双向循环链表	s->prior=p->prior;	p->prior->next=s;	s->next=p;	p->prior=s;	return 1;}

void DelElem(SeqList *A, SeqList B){	int i, pos;	DataType e;	for(i = 0; i < B.length; i++)	{		if(GetElem(B, i + 1, &e)) /* 依次把B中的每个元素取出来 */		{			if( (pos = LocateList(*A, e, compare )) >= 1)				ListDelete(A, pos, &e );		}	}}

int main(){	SqList L;	printf("%ld/n",sizeof(L));	InitSqList(L);	int i;	for(i=0;i<20;++i)		push_back(L,i);	Display(L);	printf("L.length :%d/n",L.length);	printf("listlength:%d/n",ListLength(L));	Elem e,prio,next;	GetElem(L,2,e);	PriorElem(L,prio,e);	NextElem(L,next,e);	printf("the number 2 tumple:%d/n",e);	printf("prio e:%d/n",prio);	printf("next e:%d/n",next);	ListInsert(L,8,10000);	Display(L);	LocateList(L,10000);	DeleteK(L,5,3);	Display(L);	DestroyList(L);	printf("size of a.length :%d/n",L.listsize);	if(ListEmpty(L))		printf("empty!/n");		/*char* p = NULL;	p=(char*)malloc(10*sizeof(char));	if(p==NULL)	{		printf("filure");		exit(1);	}	printf("%p/n",p);	strcpy(p,"abc");	printf("%c/n%c/n%c/n",*p,*p+1,*p+2);	printf("%p/n%p/n",p,p+1);	//if(p!=NULL)		free(p);	//p=NULL;		//DestroyList(L);	//Display(L);*/ return 0;}

void ListDelete(pListHeader plh, unsigned int index){    pListNode pNode = GetElem(plh, index);    pListNode tmp = pNode;    if(index == 1)    {        plh->next = pNode->next;    }    else    {        pListNode pPriorNode = PriorElem(plh, pNode);        pPriorNode->next = pNode->next;    }    free(tmp);    (plh->ListSize)--;}