STL之组合型函数适配器f(g(x)),f(g(x1,x2)),f(g(x),h(x)),f(g(x1),h(x2))
组合型函数分成以下几种，自己写函数适配器
f(g(elem)) ------> compose_f_gxf(g(elem1,elem2)) ------> compose_f_gxyf(g(elem),h(elem)) ------> compose_f_gx_hxf(g(elem),h(elem2)) ------> compose_f_gx_hy...
下面是具体的例子，慢慢琢磨：
#include<iostream>#include<vector>#include<algorithm>#include<functional>#include<iterator>using namespace std;template<typename Op1,typename Op2>class compose_f_gx_t:public unary_function<typename Op2::argument_type,typename Op1::result_type>{private:Op1 op1;Op2 op2;public:compose_f_gx_t(const Op1& o1,const Op2& o2):op1(o1),op2(o2){}typename Op1::result_type operator()(const typename Op2::argument_type& x)const {return op1(op2(x));}};template<typename Op1,typename Op2>inline compose_f_gx_t<Op1,Op2> compose_f_gx(const Op1& o1,const Op2& o2){return compose_f_gx_t<Op1,Op2>(o1,o2);}int main(){vector<int>v;for(int i=1;i<=9;++i){v.push_back(i);}for(vector<int>::iterator itera=v.begin();itera!=v.end();++itera){cout<<*itera<<" ";}cout<<endl;transform(v.begin(),v.end(),ostream_iterator<int>(cout," "),compose_f_gx(bind2nd(multiplies<int>(),5),bind2nd(plus<int>(),10)));cout<<endl;system("pause");return 0;}
#include<iostream>#include<vector>#include<algorithm>#include<functional>using namespace std;template<typename Op1,typename Op2,typename Op3>class compose_f_gx_hx_t:public unary_function<typename Op2::argument_type,typename Op1::result_type>{private:Op1 op1;Op2 op2;Op3 op3;public:compose_f_gx_hx_t(const Op1& o1,const Op2& o2,const Op3& o3):op1(o1),op2(o2),op3(o3){}typename Op1::result_type operator()(const typename Op2::argument_type& x)const{return op1(op2(x),op3(x));}};template<typename Op1,typename Op2,typename Op3>inline compose_f_gx_hx_t<Op1,Op2,Op3>compose_f_gx_hx(const Op1& o1,const Op2& o2,const Op3& o3){return compose_f_gx_hx_t<Op1,Op2,Op3>(o1,o2,o3);}int main(){ vector<int>v;for(int i=1;i<=9;++i){v.push_back (i);}for(vector<int>::iterator itera=v.begin();itera!=v.end();++itera){cout<<*itera<<" ";}cout<<endl;vector<int>::iterator it;it=remove_if(v.begin(),v.end(),compose_f_gx_hx(logical_and<bool>(),bind2nd(greater<int>(),4),bind2nd(less<int>(),7)));v.erase(it,v.end());for(vector<int>::iterator iterb=v.begin();iterb!=v.end();++iterb){cout<<*iterb<<" ";}cout<<endl;system("pause");return 0;}
#include<iostream>#include<cctype>#include<algorithm>#include<string>#include<vector>#include<functional>using namespace std;template<typename Op1,typename Op2,typename Op3>class compose_f_gx_hy_t:public binary_function<typename Op2::argument_type,typename Op3::argument_type,typename Op1::result_type>{private:Op1 op1;Op2 op2;Op3 op3;public:compose_f_gx_hy_t(const Op1& o1,const Op2& o2,const Op3& o3):op1(o1),op2(o2),op3(o3){};typename Op1::result_type operator()(const typename Op2::argument_type& x,const typename Op3::argument_type& y)const{return op1(op2(x),op3(y));}};template<typename Op1,typename Op2,typename Op3>inline compose_f_gx_hy_t<Op1,Op2,Op3> compose_f_gx_hy(const Op1& o1,const Op2& o2,const Op3& o3){return compose_f_gx_hy_t<Op1,Op2,Op3>(o1,o2,o3);}int main(){string s("Internationalization");string sub("Nation");string::iterator it;it=search(s.begin(),s.end(),sub.begin(),sub.end(),compose_f_gx_hy(equal_to<int>(),ptr_fun(::toupper),ptr_fun(::toupper)));if(it!=s.end()){cout<<"\""<<sub<<"\" is part of\""<<s<<"\""<<endl;}system("pause");return 0;}