内存拷贝函数不同写法的效率分析

#include<iostream>#include<algorithm>#include<string>using namespace std;void OverFlow(const int &max){ int &tmp=const_cast<int&>(max); tmp=200; cout<<"the value of tmp"<<tmp<<endl;//输出200 cout<<"max in the function"<<max<<endl;//输出200}int main(){ const int maxint=100; const int *ptr=&maxint; OverFlow(maxint); cout<<"max in the main"<<maxint<<endl;//值为100，说明编译器用100做了替换。 // 等效语句为 cout<<"max in the main"<<100<<endl; cout<<"the value of ptr"<<*ptr<<endl;//值为200，说明maxint的值被改变了return 0;}