C++ 函数模板示例 2 (配合decltype)

来源：互联网发布：mac 怎么读取exe 编辑：程序博客网时间：2024/06/05 10:52

#include "stdafx.h"#include <iostream>#include <iomanip>#include <string.h>#include <new>using std::cout;using std::cin;using std::endl;using std::setw;template<class T1, class T2> auto product(T1 v1[], T2 v2[], size_t count) -> decltype(v1[0]*v2[0]){decltype(v1[0]*v2[0]) sum(0);for(size_t i=0;i<count;i++) sum += v1[i]*v2[i];return sum;}int main(int argc,_TCHAR* argv[]){double x[] = {100.5,99.5,88.7,77.8};short y[] = {3,4,5,6};long z[] = {11L,22L,33L,44L};size_t n=4;cout <<"result type is " <<typeid(product(x,y,n)).name()<<endl;cout<<"result is "<<product(x,y,n)<<endl;cout <<"result type is " <<typeid(product(z,y,n)).name()<<endl;cout<<"result is "<<product(z,y,n)<<endl;return 0;}

</pre><pre name="code" class="cpp">上面代码的运行结果是：

更多完整的示例，可以参见《Visual C++ 2012入门经典》一书的212页，6.8节：使用函数的示例。

0 0