写点C++ 学习记录 充数

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#include "stdafx.h" #include <cstdlib> #include <iostream>   using namespace std;   int fcmp(const void* elem,const void* elem2); void sample1(); void sample2();   int _tmain(int argc, _TCHAR* argv[]) {     sample1();     cout << "*******************" << endl;     sample2();       return 0; }     template <class T> struct plus{     T operator()(const T& x,const T& y)const{return x+y;} };   template <class T> struct minus{     T operator()(const T& x,const T& y)const{return x-y;} };   void sample2() {     plus<int>plusobj;     minus<int>minusobj;       cout << plusobj(3,5) << endl;     cout << minusobj(3,5) << endl;       cout << plus<int>()(43,50) << endl;     cout << minus<int>()(43,50) << endl;   }     void sample1() {     int ia[10] = {32,92,67,58,10,4,25,52,59,54};     for(int i =0;i <10;i++)     {         cout << ia[i] << " ";     }     cout << endl;       qsort(ia,sizeof(ia)/sizeof(int),sizeof(int),fcmp);       for(int i =0;i <10;i++)     {         cout << ia[i] << " ";     }     cout << endl; }   int fcmp(const void* elem1,const void* elem2) {     const int* i1 = (const int*)elem1;     const int* i2 = (const int*)elem2;       if(*i1 < *i2)         return -1;     else if(*i1 == *i2)         return 0;     else if(*i1 > *i2)         return 1; }

传递函数指针与function call 示例