函数定义问题

[lihorse_1043]

#include <iostream>
#include <fstream>
using namespace std;
class SMatrix {
public:
SMatrix(char *filename);
~SMatrix();
void printSMatrix()const;
void printList()const;
void insert(int x, int y, int v);
friend SMatrix add(SMatrix x, SMatrix y);//我想做两个矩阵相加的函数，不知道如何定义，请教一下各位。如果能给出代码更好了，呵呵，谢了。
private:
struct Node {
int row, col, value;
Node *next;
};
int size;
Node *listPtr;
};

[珍惜生命远离CPP]

friend SMatrix add(const SMatrix& x,const SMatrix& y);//
这样定义就好

[wangdeqie]

#include <iostream> 
#include <fstream> 
using namespace std; 
class SMatrix 
{ 
public: 
  SMatrix(char *filename); 
  ~SMatrix(); 
  void printSMatrix()const; 
  void printList()const; 
  void insert(int x, int y, int v); 
  SMatrix add(const SMatrix &y);//可以这么写
  private: 
  struct Node 
  { 
  int row, col, value; 
  Node *next; 
  }; 
  int size; 
  Node *listPtr; 
};

void main()
{

}

[wangdeqie]

1.写在类里面用一元（另一个是隐含的this对象）
2.写在类外面用二元

[baihacker]

楼主可以去参考blitz（有点难）

如果只是与简单的矩阵应用 看了CwMtx以后，你的水平会有所长进的。

[wangdeqie]

//这是偶以前写过的，功能应该类似，楼主可以参考下^_^
//---xcept.h---
class NoMem
{
public:
	NoMem(){}
};
void my_new_handler()
{
	throw NoMem();
}
class OutOfBounds
{ 
public: 
	OutOfBounds(){} 
}; 
class BadInitializers
{
public:
	BadInitializers(){}
};
class SizeMismatch
{
public:
	SizeMismatch(){}
};

//---main.cpp---
#include<iostream>
#include"xcept.h"
using namespace std;
template<class T>
class SparseMatrix;
template<class T>
class Term
{
	friend SparseMatrix<T>;
private:
	int row,col;
	T value;
};
template<class T>
class SparseMatrix
{
	
	friend ostream& operator<<(ostream& out,const SparseMatrix<T>& x)
	{
		out<<"rows= "<<x.rows<<"columns= "<<x.cols<<endl;
		out<<"nozero terms= "<<x.terms<<endl;
		for(int i=0;i<x.terms;i++)
			out<<"a("<<x.a[i].row<<','<<x.a[i].col<<")="<<x.a[i].value<<endl;
		return out;
	}

	friend istream& operator>>(istream& in,SparseMatrix<T>& x)
	{
		cout<<"Enter number of rows,columns, and terms "<<endl;
		in>>x.rows>>x.cols>>x.terms;
		if(x.terms>x.MaxTerms)
			throw NoMem();
		for(int i=0;i<x.terms;i++)
		{
			cout<<"Enter row, colum, and value of term "<<(i+1)<<endl;
			in>>x.a[i].row>>x.a[i].col>>x.a[i].value;
		}
		return in;
	}
	
public:
	SparseMatrix(int maxTerms=10);
	~SparseMatrix(){delete [] a;}
	void Transpose(SparseMatrix<T>& b)const;
	void Add(const SparseMatrix<T>& b,SparseMatrix<T>& c)const;
	void Output(ostream& out)const;
	void Input(istream& in);
private:
	void Append(const Term<T>& t);
	int rows,cols;
	int terms;
	Term<T>* a;
	int MaxTerms;
};
template<class T>
SparseMatrix<T>::SparseMatrix(int maxTerms)
{
	if(maxTerms<1)
		throw BadInitializers();
	MaxTerms=maxTerms;
	a=new Term<T>[MaxTerms];
	terms=rows=cols=0;
}
template<class T>
void SparseMatrix<T>::Append(const Term<T>& t)
{
	if(terms>=MaxTerms)
		throw NoMem();
	a[terms]=t;
	terms++;
}
template<class T>
void SparseMatrix<T>::Add(const SparseMatrix<T>& b,SparseMatrix<T>& c)const
{
	if(rows!=b.rows||cols!=b.cols)
		throw SizeMismatch();
	c.rows=rows;
	c.cols=cols;
	c.terms=0;
	int ct=0,cb=0;
	while(ct<terms && cb<b.terms)
	{
		int indt=a[ct].row*cols+a[ct].col;
		int indb=b.a[cb].row*cols+b.a[cb].col;
		if(indt<indb)
		{
			c.Append(a[ct]);
			ct++;
		}
		else
		{
			if(indt==indb)
			{
				if(a[ct].value+b.a[cb].value)
				{
					Term<T> t;
					t.row=a[ct].row;
					t.col=a[ct].col;
					t.value=a[ct].value+b.a[cb].value;
					c.Append(t);
				}
				ct++;
				cb++;
			}
			else
			{
				c.Append(b.a[cb]);
				cb++;
			}
		}
	}
	for(;ct<terms;ct++)
		c.Append(a[ct]);
	for(;cb<b.terms;cb++)
		c.Append(b.a[cb]);
}
template<class T>
void SparseMatrix<T>::Output(ostream& out)const
{
	out<<"rows= "<<rows<<" "<<"columns= "<<cols<<endl;
	out<<"nozero terms= "<<terms<<endl;
	for(int i=0;i<terms;i++)
	out<<"a("<<a[i].row<<','<<a[i].col<<")="<<a[i].value<<endl;
}
template<class T>
ostream& operator<<(ostream& out,const SparseMatrix<T>& x)
{
	x.Output(out);
	return out;
}

template<class T>
void SparseMatrix<T>::Input(istream& in)
{
	cout<<"Enter number of rows,columns, and terms: "<<endl;
	in>>rows>>cols>>terms;
	if(terms>MaxTerms)
		throw NoMem();
	for(int i=0;i<terms;i++)
	{
		cout<<"Enter row, colum, and value of term: "<<(i+1)<<endl;
		in>>a[i].row>>a[i].col>>a[i].value;
	}
}
template<class T>
istream& operator>>(istream& in,SparseMatrix<T>& x)
{
	x.Input(in);
	return in;
}

void main()
{
	
	SparseMatrix<int> a(4);
	SparseMatrix<int> b(4);
	SparseMatrix<int> c(4);
	cin>>a;
	cout<<a<<endl;
	cin>>b;
	cout<<b<<endl;
	a.Add(b,c);
	cout<<c<<endl;
	
}

[lihorse_1043]

学习中，谢了。