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boost::bind实践
第一部分源码为基础实践:
1 /*Beyond the C++ Standard Library ( An Introduction to Boost )[CN].chm*/ 2 /*bind的用法*/ 3 4 #include <iostream> 5 #include <algorithm> 6 #include <functional> 7 #include <vector> 8 9 #include <boost/bind/bind.hpp> 10 #include <boost/bind/apply.hpp> 11 #include <boost/smart_ptr/shared_ptr.hpp> 12 13 using namespace std; 14 using namespace boost; 15 16 int f(int a, int b) 17 { 18 return a + b; 19 } 20 21 int g(int a, int b, int c) 22 { 23 return a + b + c; 24 } 25 26 bool preFind(int a, int b) 27 { 28 return a<b; 29 } 30 bool preFind2(int a, int b, int c) 31 { 32 return a<b && a<c; 33 } 34 struct predicate 35 { 36 typedef void result_type; 37 void operator() (int a, int b) 38 { 39 cout << a << "+" << b << "=" << a+b << endl; 40 } 41 }; 42 struct X 43 { 44 void f(int a) 45 { 46 cout << "a = " << a << endl; 47 } 48 void f2(int a, int b) 49 { 50 cout << a << "+" << b << "=" << a+b << endl; 51 } 52 predicate pre; 53 int arrElem; 54 int *parrElem; 55 }; 56 57 void main() 58 { 59 int arr[5] = {1, 2, 3, 4, 5}; 60 //int ret1 = std::count_if(arr, arr+5, boost::bind(preFind, _1, 2)); 61 //cout << ret1 << endl; 62 //int ret2 = std::count_if(arr, arr+5, boost::bind(preFind, 2, _2)); 63 //cout << ret2 << endl; 64 //std::for_each (arr, arr+5, boost::bind(preFind, _1, 2)); 65 //std::for_each (arr, arr+5, boost::bind(predicate(), _1, 2)); 66 //std::for_each (arr, arr+5, boost::bind(boost::type<void>(), predicate(), _1, 2)); 67 //std::for_each (arr, arr+5, boost::bind(preFind2, _1, 2, 3)); 68 //std::for_each (arr, arr+5, boost::bind(preFind2, _1, 2, _1)); 69 //boost::bind(preFind2, 5, _2, 3); 70 //std::for_each (arr, arr+5, boost::bind(preFind2, 5, _2, 3)); 71 72 //boost::bind(preFind, _1, 2); 73 //boost::bind(preFind, _2, 2); 74 //boost::bind(preFind, _1, _2); 75 //boost::bind(preFind, _2, _1); 76 //boost::bind(preFind2, _1, _2, _3); 77 //boost::bind(predicate(), _1, _2); 78 //boost::bind(boost::type<void>(), predicate(), _1, _2); 79 80 //X x; 81 //boost::bind(&X::f, boost::ref(x), _1); 82 //boost::bind(&X::f, _1, 1); 83 //boost::bind(&X::f, _1, _2); 84 //boost::bind(&X::pre, _1); 85 //std::for_each (arr, arr+5, boost::bind(&X::f, x, _1)); 86 //std::for_each (arr, arr+5, boost::bind(&X::f2, boost::ref(x), _1, 2)); 87 //std::for_each (arr, arr+5, boost::bind(&X::f2, &x, _1, 2)); 88 //boost::shared_ptr<X> p(new X); 89 //std::for_each (arr, arr+5, boost::bind(&X::f2, p, _1, 2)); 90 std::vector<X*> arrs; 91 for (int i=0 ; i!=5 ; ++i) 92 { 93 arrs.push_back(new X); 94 } 95 std::for_each (arrs.begin(), arrs.end(), boost::bind(&X::arrElem, _1)); 96 std::for_each (arrs.begin(), arrs.end(), boost::bind(&X::f, _1, 2)); 97 }
第二部分源码为实际应用:
1 /*Beyond the C++ Standard Library ( An Introduction to Boost )[CN].chm*/ 2 /*bind的用法*/ 3 4 #include <iostream> 5 #include <algorithm> 6 #include <functional> 7 #include <vector> 8 9 #include <boost/bind/bind.hpp> 10 #include <boost/smart_ptr/shared_ptr.hpp> 11 12 using namespace std; 13 using namespace boost; 14 15 class status 16 { 17 public: 18 std::string name_; 19 bool ok_; 20 public: 21 status(const std::string& name):name_(name),ok_(true) {} 22 void break_it() { ok_=false; } 23 bool is_broken() const { return ok_; } 24 void report() const 25 { 26 std::cout << name_.c_str() << " is " << (ok_ ? "working nominally":"terribly broken") << std::endl; 27 } 28 }; 29 30 void nine_arguments( int i1,int i2,int i3,int i4, int i5,int i6,int i7,int i8, int i9) 31 { 32 std::cout << i1 << i2 << i3 << i4 << i5 << i6 << i7 << i8 << i9 << ‘\n‘; 33 } 34 int main() 35 { 36 int i1=1,i2=2,i3=3,i4=4,i5=5,i6=6,i7=7,i8=8,i9=9; 37 (boost::bind(&nine_arguments,_9,_2,_1,_6,_3,_8,_4,_5,_7))(i1,i2,i3,i4,i5,i6,i7,i8,i9); 38 39 40 //std::vector<status> statuses; 41 //statuses.push_back(status("status 1")); 42 //statuses.push_back(status("status 2")); 43 //statuses.push_back(status("status 3")); 44 //statuses.push_back(status("status 4")); 45 //statuses[1].break_it(); 46 //statuses[2].break_it(); 47 ////method 1: 48 //for (std::vector<status>::iterator it=statuses.begin(); it!=statuses.end();++it) 49 //{ 50 // it->report(); 51 //} 52 ////method 2: ok 53 //std::for_each( statuses.begin(), statuses.end(), std::mem_fun_ref(&status::report)); 54 ////method 3: ok 55 //std::for_each( statuses.begin(), statuses.end(), boost::bind(&status::report, _1)); 56 ////others ok 57 //std::for_each( statuses.begin(), statuses.end(), boost::bind(&status::name_, _1)); 58 59 //std::vector<status*> p_statuses; 60 //p_statuses.push_back(new status("status 1")); 61 //p_statuses.push_back(new status("status 2")); 62 //p_statuses.push_back(new status("status 3")); 63 //p_statuses.push_back(new status("status 4")); 64 //p_statuses[1]->break_it(); 65 //p_statuses[2]->break_it(); 66 ////method 2: ok 67 //std::for_each( p_statuses.begin(), p_statuses.end(), std::mem_fun(&status::report)); 68 ////method 3: ok 69 //std::for_each( p_statuses.begin(), p_statuses.end(), boost::bind(&status::report, _1)); 70 71 std::vector<boost::shared_ptr<status> > s_statuses; 72 s_statuses.push_back( boost::shared_ptr<status>(new status("status 1"))); 73 s_statuses.push_back( boost::shared_ptr<status>(new status("status 2"))); 74 s_statuses.push_back( boost::shared_ptr<status>(new status("status 3"))); 75 s_statuses.push_back( boost::shared_ptr<status>(new status("status 4"))); 76 s_statuses[1]->break_it(); 77 s_statuses[2]->break_it(); 78 //method 2: error 79 //std::for_each( s_statuses.begin(), s_statuses.end(), std::mem_fun(&status::report)); 80 //method 3: ok 81 std::for_each( s_statuses.begin(), s_statuses.end(), boost::bind(&status::report, _1)); 82 83 84 }
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