app.cpp源代码：
#include "stdio.h"
#include "windows.h"
//#include "dll.h"
#include <iostream>

using namespace std;

typedef int (/*CALLBACK*/* padd)(int a,int b); //定义函数指针类型

void main()
{

HINSTANCE hInstance=LoadLibrary("Dll项目.dll");
padd add=
   (padd)GetProcAddress(hInstance,"add");
if(!add)
{
   cout<<"动态连接库库函数未找到"<<endl;

}

cout<<"3+5="<<add(3,5)<<endl;
FreeLibrary(hInstance);

//HINSTANCE hDLL;
//hDLL=LoadLibrary("Dll项目.dll" );    //加载动态链接库

//padd vLength=
// (padd)GetProcAddress(hDLL,"add"); //获得函数地址
//int a=9;
//int b=8;
//// float a=3.0f,b=4.0f;
//if(!vLength)
//{printf("没有找到函数地址");}
////printf("The length of(a,b) is %d\n",vLength(a,b));
//int k=0;
//k=vLength(a,b);
//FreeLibrary(hDLL);

HINSTANCE hDLL;
hDLL=LoadLibrary("dlldef.dll" );    //加载动态链接库

funLength P=(funLength)GetProcAddress(hDLL,"aa"); //获得函数地址

//float a=3.0f,b=4.0f;
int a=1,b =2;
printf("The length of(a,b) is %d\n",P(a,b));
FreeLibrary(hDLL);

}
//
//
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