【c++程序】friend与operator

#include<iostream>using namespace std;//*********************************************************//自定义格式控制符//无参的，可以是对象class _HEXUB{friend ostream& operator<<(ostream &o,const _HEXUB &h){return o<<hex<<uppercase<<showbase;}};const _HEXUB hexub=_HEXUB();//定义成全局//无参的，也可以是函数ostream& func(ostream& o){return o<<dec<<showpos;}class wf{unsigned int w;char f;public:wf(unsigned int w,char fill=' '):w(w),f(fill){}friend ostream& operator <<(ostream& o,const wf& x){o.width(x.w);o.fill(x.f);return o;}};int main(){cout<<hexub<<123<<endl;//ox7B//friend ostream& operator<<(ostream &cout,const _HEXUB &hexub)cout<<wf(10,'*')<<"good"<<endl;cout<<wf(8)<<"good"<<endl;cout<<func<<123<<endl;}