C++编写动态链接库供VFP调用

//C++代码 dll.h

#ifndef LIB_H

#define LIB_H

extern "C" _declspec(dllexport) char* enciphering(char *ch,int &key);

extern "C" _declspec(dllexport) char* deciphering(char *ch,int &key);

#endif

//C++代码 Sercret.cpp

#include <iostream>

#include "dll.h"

using namespace std;

char* enciphering(char *ch,int &key)

{

    char *str=new char[100];

    int i=0,x;

    bool decide=true;

    while(ch[i])

    {

        if(ch[i]>='a'&&ch[i]<='z')

        {

            x = ch[i] + i + key + 1;

            while(decide)

            {

                if(x>'z')

                    x-=26;

                else

                    decide=false;

            }

            decide=true;

            str[i]=x;

        }

        else

            str[i]=ch[i];

        i++;

    }

    return str;

}

char* deciphering(char *ch,int &key)

{

    char *str=new char[100];

    int i=0,x;

    bool decide=true;

    while(ch[i])

    {

        if(ch[i]>='a'&&ch[i]<='z')

        {

            x=ch[i]-i-1-key;

            while(decide)

            {

                if(x<'a')

                    x+=26;

                else

                    decide=false;

            }

            decide=true;

            str[i]=x;

        }

        else

str[i]=ch[i];

        i++;

    }

    return str;

}

//编译后dll被VFP调用

Declare String enciphering in s_sercret.dll String @, Integer @

Declare String deciphering in s_sercret.dll String @, Integer @