#include <iostream.h>                #include <stdio.h>		enum Boolean { False, True };		struct Triple { int row, col;  float value; };					//三元組類的定義		class Matrix;										//稀疏矩陣類的前視聲明		class MatrixNode {									//矩陣結點類的定義		friend class Matrix;		friend istream & operator >> ( istream &, Matrix & );			//矩陣讀入                friend ostream & operator << ( ostream &, Matrix & );		private:		   MatrixNode *down, *right;							//列/行鏈表指針		   Boolean head;									//結點類型		   union { Triple triple;  MatrixNode *next; };				//無名聯合		   MatrixNode ( Boolean, Triple* );						//構造函數		};		MatrixNode::MatrixNode ( Boolean b, Triple *t ){				//構造函數		   head = b;									//結點類型		   if ( b ) { right = next = this; }						//各行/列鏈表的表頭結點		   else triple = *t;									//頭結點鏈表的表頭或非零元素結點		}		typedef MatrixNode *MatrixNodePtr;						//一個指針數組		class Matrix {									//稀疏矩陣的類定義		friend istream & operator >> ( istream &, Matrix & );                friend ostream & operator << ( ostream &, Matrix & );		public:		   ~Matrix ( );									//析構函數		private:		   MatrixNode *headnode; 							//稀疏矩陣的表頭		};		istream & operator >> ( istream & is, Matrix & matrix )	//讀入稀疏矩陣, 建立它的鏈表表示		{		   Triple s;  int p;		   is >> s.row >> s.col >> s.value; 						//讀入矩陣行數、列數和非零元素個數		   if ( s.row > s.col ) p = s.row;						//確定行/列鏈表表頭結點個數p		   else p = s.col;									// p = max { s.row, s.col }		   matrix.headnode = new MatrixNode ( False, &s );				//創建表的表頭結點		   if ( !p ) { matrix.headnode->right = matrix.headnode;  return is; }	//至少一行或一列		   MatrixNodePtr *H = new MatrixNodePtr [ p ];				//初始化表頭指針數組，指向各鏈表頭		   for ( int i=0; i<p; i++ ) H[i] = new MatrixNode ( True, 0 );		//指向各鏈表頭結點		   int CurrentRow = 0;		   MatrixNode *last = H[0];							//last為當前行的最后結點指針		   for ( i=0; i<s.value; i++ ) {							//輸入三元組, s.value給出三元組個數			 Triple t;		 is >> t.row >> t.col >> t.value;					//輸入三元組			 if ( t.row > CurrentRow ) {						//行號大于當前行號，閉合當前行			    last->right = H[CurrentRow];					//在行的方向向表頭結點拉鏈			    CurrentRow = t.row;  last = H[CurrentRow];			//當前行改變為新的一行			 }			 last = last->right = new MatrixNode ( False, &t );			//新結點鏈入行鏈表，last跟上			 H[t.col]->next = H[t.col]->next->down = last;			//鏈入列鏈表，next記下該結點地址		   }		   last->right = H[CurrentRow];						//閉合最后一行		   for ( i=0; i<s.col; i++ ) H[i]->next->down = H[i];			//閉合所有列鏈表		   for ( i=0; i<p-1; i++ ) H[i]->next = H[i+1];				//所有表頭結點鏈接在一起		   H[p-1]->next = matrix.headnode;  matrix.headnode->right = H[0];		   delete [ ] H;		   return is;		}	      /*	if ( first != NULL ) {								//鏈表不空		   CircListNode<Type> *second = first->link;			//循環鏈表的第二個結點		   first->link = av;    av = second;					//第一個結點鏈接到av		   first = NULL;		}		if ( av == NULL ) newnode = new CircListNode<Type>;	//可利用空間表為空，動態分配		else { newnode = av;  av = av->link; }				//不空，從可利用空間表分配		*/                MatrixNode *av;		Matrix::~Matrix ( ) {		//將所有結點回收到可利用空間表中, 這個表是用right域鏈接的。av是一個具有MatrixNode*		//類型的全局變量, 且指向它的前端第一個結點。		   if ( headnode == NULL ) return;					//空鏈表, 無法回收		   MatrixNode *x = headnode->right, *y;		   headnode->right = av;  av = headnode;				//回收表頭結點的循環鏈表		   while ( x != headnode ) {						//按行回收各行的循環鏈表		      y = x->right;  x->right = av;  av = y;			//回收行 (循環) 鏈表		      x = x->next;							//下一行		   }		   headnode = NULL;		}		ostream & operator << ( ostream & os, Matrix & matrix )		{		    MatrixNode *current = matrix.headnode , *temp;		    cout << "row:  " << current->triple.row << endl;		    cout << "column: " << current->triple.col << endl;		    cout << "nonzero: " << current->triple.value << endl;		    cout << "order in column:" << endl;		    temp = current = current->right;		    for (int column = 0 ; column < matrix.headnode->triple.col; column++) {			cout << "column " << column << " : " ;			temp = temp->down ;			while ( temp != current ) {			    cout << "(" << temp->triple.row << ",";			    cout << temp->triple.col << ",";			    cout << temp->triple.value << ") ";			    temp = temp->down;			};			cout << endl;			temp = current = current->next;		    }		    cout << "order in row:" << endl;		    temp = current = current->right;		    for (int row = 0; row < matrix.headnode->triple.row; row++) {			cout << "row " << row << " : " ;			temp = temp->right ;			while ( temp != current ) {			    cout << "(" << temp->triple.row << ",";			    cout << temp->triple.col << ",";			    cout << temp->triple.value << ") ";			    temp = temp->right;			};			cout << endl;			temp = current = current->next;		    }		    return os;		}