function object用法

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 1 // Generic findMax, with a function object, version #1 2 // Precondition,  a.size() > 0 3 #include <iostream> 4 #include <vector> 5 #include <string.h> 6 using namespace std; 7  8 template <class Object, class Comparator> 9 const Object& findMax(const vector<Object> &arr, Comparator cmp)10 {11     int maxIndex = 0;12     for(int i = 1; i < arr.size(); i++) {13         if(cmp.isLessThan(arr[maxIndex], arr[i]))14             maxIndex = i;15     }16     return arr[maxIndex];17 }18 19 #include <functional>20 template <class Object>21 const Object& findMax(const vector<Object> &arr)22 {23     return findMax(arr, less<Object>() );24 }25 26 class CaseInsensitiveCompare {27     public:28             bool isLessThan(const string &lhs, const string &rhs) const29                 {return (stricmp(lhs.c_str(), rhs.c_str())< 0); }30 };31 32 int main() 33 {34     vector<string> arr(3);35     arr[0] = "ZEBRA"; arr[1] = "alligator"; arr[2] = "crocodile";36     cout << findMax(arr, CaseInsensitiveCompare()) << endl;37     //cout << findMax(arr) << endl;38     return 0;39 }40 41     42             43     44