函式物件和函式介面卡

用到以下演算法：

templatetype accumulate(inputiterator first, inputiterator last, type val, binaryfunction binaryop);

#include #include //包含數值演算法標頭檔案

using namespace std;
//定義乙個普通函式
int mult(int x, int y) ; 
int main() ;
const int n = sizeof(a) / sizeof(int);
cout << "the result by multipling all elements in a is "
<< accumulate(a, a + n, 1, mult)
<< endl;
return 0;
}

//10_14.cpp

#include #include //包含數值演算法標頭檔案
using namespace std;
class multclass 
};int main() ;
const int n = sizeof(a) / sizeof(int);
cout << "the result by multipling all elements in a is "
<< accumulate(a, a + n, 1, multclass()) //將類multclass傳遞給通用演算法
<< endl;
return 0;
}

//10_15.cpp

#include #include //包含數值演算法標頭檔案
#include //包含標準函式物件標頭檔案
using namespace std; 
int main() ;
const int n = sizeof(a) / sizeof(int);
cout << "the result by multipling all elements in a is 「
<< accumulate(a, a + n, 1, multiplies())
<< endl; //將標準函式物件傳遞給通用演算法
return 0;
}

// 10_16.cpp

#include #include#include#includeusing namespace std;
int main() ;
const int n = sizeof(intarr) / sizeof(int);
vectora(intarr, intarr + n);
cout << "before sorting:" << endl;
copy(a.begin(),a.end(),ostream_iterator(cout,"\t"));
cout << endl;
sort(a.begin(), a.end(), greater());
cout << "after sorting:" << endl;
copy(a.begin(),a.end(),ostream_iterator(cout,"\t"));
cout << endl;
return 0;
}

函式指標介面卡：ptr_fun

成員函式介面卡：ptrfun、ptrfun_ref

//10_17.cpp

#include #include#include#includeusing namespace std;
int main() ;
const int n = sizeof(intarr) / sizeof(int);
vectora(intarr, intarr + n);
vector::iterator p = find_if(a.begin(), a.end(), bind2nd(greater(), 40));
if (p == a.end())
cout << "no element greater than 40" << endl;
else
cout << "first element greater than 40 is: " << *p << endl;
return 0;}注：
find_if演算法在stl中的原型宣告為：
templateinputiterator find_if(inputiterator first, inputiterator last, unarypredicate pred);
它的功能是查詢陣列[first, last)區間中第乙個pred(x)為真的元素。

// 10_18.cpp

#include #include#include#includeusing namespace std;
bool g(int x, int y) 
int main() ;
const int n = sizeof(intarr) / sizeof(int);
vectora(intarr, intarr + n);
vector::iterator p;
p = find_if(a.begin(), a.end(), bind2nd(ptr_fun(g), 40));
if (p == a.end())
cout << "no element greater than 40" << endl;
else
cout << "first element greater than 40 is: " << *p << endl;
p = find_if(a.begin(), a.end(), not1(bind2nd(greater(), 15)));
if (p == a.end())
cout << "no element is not greater than 15" << endl;
else
cout << "first element that is not greater than 15 is: " << *p << endl;
p = find_if(a.begin(), a.end(), bind2nd(not2(greater()), 15));
if (p == a.end())
cout << "no element is not greater than 15" << endl;
else
cout << "first element that is not greater than 15 is: " << *p << endl;
return 0;
}

//10_19.cpp

#include #include #include #include using namespace std;
struct car 
void display() const 
};int main() 

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