c++ post

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<curl/curl.h>
#include<string>
#include<iostream>
#include<fstream>
#include<openssl/pem.h>
#include<openssl/bio.h>
#include<openssl/evp.h>
#include <openssl/buffer.h>
#include<unistd.h>
#include<openssl/md5.h>
using namespace std;


char * base64Encode(const char *buffer, int length)
{
    BIO *bmem = NULL;
    BIO *b64 = NULL;
    BUF_MEM *bptr;

    b64 = BIO_new(BIO_f_base64());
    //BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
    bmem = BIO_new(BIO_s_mem());
    b64 = BIO_push(b64, bmem);
    BIO_write(b64, buffer, length);
    BIO_flush(b64);
    BIO_get_mem_ptr(b64, &bptr);
    BIO_set_close(b64, BIO_NOCLOSE);

    char *buff = (char *)malloc(bptr->length + 1);
    memcpy(buff, bptr->data, bptr->length);
    buff[bptr->length] = '\0';
    BIO_free_all(b64);

    return buff;
}

int main(int argc,char *argv[]) {

    string PAHT = "test.png";
    string url = "http://www.seemmark.com/external-api/external/captcha/ve";
    string key = "58f0a437e7798958a686bb33";
    string codeID = "1001adf11eefe";
    string userId = "1234";
    //cin>>userId;
    FILE *p = fopen("test.png", "rb");
        // 判断打开文件是否成功

        // 定义读取文件的缓冲区
        char buf[1024];
        // 循环读取文件
        string s;
        while(fread(&buf,sizeof(char),sizeof(buf),p) > 0){

            string tmp = buf;
            s += tmp;
            memset(buf,0,sizeof(buf));
    }
    cout<<s<<endl;
    const char *buffer = s.c_str();
     char * buff;
    buff = base64Encode(buffer, s.length());
    string image  = buff;
    //cout<<image<<endl;
    codeID = "codeID=" + codeID;
    image = "image=" + image;
    userId = "userId" + userId;
    string param = codeID + "&" + image + "&" + userId + "&" + key;
    //cout<<param<<endl;
    MD5_CTX ctx;
    unsigned char md[16];
    char bufs[33] = {'\0'};
    char tmp[3] = {'0'};
    int i;
    const char *ps = param.c_str();
    MD5_Init(&ctx);
    MD5_Update(&ctx, p, param.length());
    MD5_Final(md, &ctx);

    for(i = 0; i < 16;i++)
    {
        sprintf(tmp, "%02X", md[i]);
        strcat(buf, tmp);
    }

    //printf("%s\n", buf);
    return 0;
}

http://www.seemmark.com/developer/image-captcha/sample-codes