基礎(chǔ)學(xué)習(xí)：C++重載輸入輸出符

          當(dāng)我們對一個類重載<<,>>運(yùn)算符之后,就可以直接使用cout<<x,cin>>x兩種簡單的操作
a.重載輸出運(yùn)算符<<
因重最左邊的操作數(shù)是ostream,自然就不能用類的成員函數(shù)重載,而只能以類的友元函數(shù)進(jìn)行重載
//<<函數(shù)定義格式
friend ostream operator<<(ostream&,const nameclass&)const;
//<<函數(shù)實(shí)現(xiàn)部分
ostream & operator<<(ostream& out,const classname& object)
{
//local delcare if any
//check object ostream
//output the members of the object
//...
return out;
}
b.重載輸出運(yùn)算符>>
因重最左邊的操作數(shù)是istream,自然就不能用類的成員函數(shù)重載,而只能以類的友元函數(shù)進(jìn)行重載
//<<函數(shù)定義格式
friend istream operator>>(istream&,const nameclass&)const;
//<<函數(shù)實(shí)現(xiàn)部分
istream & operator>>(istream& in,const classname& object)
{
//local delcare if any
//check object istream
//output the members of the object
//...
return in;
}  
c.<<,>>代碼實(shí)現(xiàn)
//重載函數(shù)<<,>>定義
class OpOver
{
public:
 OpOver(int i=0;int j=0){a=i;b=j;};
 friend ostream& operator<<(ostream&,const OpOver&); 
 friend istream& operator>>(istream&,const OpOver&);
 OpOver operator+(const OpOver&)const;
 bool operator==(const OpOver&)const;
private:
 int a;
 int b;
};
//重載函數(shù)<<,>>實(shí)現(xiàn)
ostream& operator<<(ostream& out,const OpOver& right)
{
 out<<right.a<<","<<right.b; 
 return out;
}
istream& operator>>(istream& in,const OpOver& right)
{
 in>>right.a>>right.b;
 return in;
}