我是 C++ 编程的新手。我有一个小练习,可以使用以下内容:使用 windows 套接字编程,使用窗口 api 函数(CreateFile、ReadFile 和 WriteFile),以及使用 seekg、seekp、tellg 和 tellp 函数。
这是我的代码中发生的事情,
打开一个
.txt
包含 URL 的文件(reddit.com、stackoverflow.com、google.com),然后读取 URL 并将strVal
.strVal
然后我使用分隔符拆分数据的值,","
然后循环开始。然后开始windows socket编程。
在循环内部,它将获取每个 URL 的 HTTP 请求并询问请求类型(
POST
或GET
)。一旦收到请求的答复,数据将在 Buffer 中。
然后我将打开一个
.txt
文件来放置收到的 3 个域的请求。
这里的例子 是 output.txt 的结果
结果很好,程序正在处理这部分,但对于程序的最后一个要求,他们希望我.txt
使用 seekg、seekp、tellg 和 tellp 更改文件内已回答数据的顺序。
我试图实现这些功能,这是我的代码。
fstream fs0 ("C:\\Documents and Settings\\Administrator\\My Documents\\output.txt", ios::in | ios::out | ios::app);
ofstream fs1 ("C:\\Documents and Settings\\Administrator\\My Documents\\output1.txt", ios::out | ios::app);
//1st
fs0.seekg(2020, ios::beg);
char ab[2020];
fs0.read(ab, sizeof(ab));
//2nd
fs0.seekg(0, ios::cur);
char dc[2020];
fs0.read(dc, sizeof(dc));
//3rd
fs0.seekg(0, ios::beg);
char abc[2000];
fs0.read(abc, sizeof(abc));
fs1.write(ab, sizeof(ab));
fs1.write(dc, sizeof(dc));
fs1.write(abc, sizeof(abc));
fs0.close();
fs1.close()
我刚刚打开.txt
插入数据的文件,然后使用 seekg 读取数据,然后将其放入缓冲区然后输出。没有意义,因为如果.txt
文件中插入了另一个域怎么办。
现在,我关心的是这部分。根据我的代码,如何使用 seekg、seekp、tellg 和 tellp 更改 txt 文件中数据的顺序?
这是我的整体代码,
int main()
{
//getting the data
HANDLE openFile;
//HANDLE openFile1;
HANDLE putdataFile;
BOOL rewriFile;
//BOOL rewriFile1;
char *strVal;
//char *strVal1;
char* point;
//char* point1;
DWORD dwNoBytetoRead = 0;
//DWORD dwNoBytetoRead1 = 0;
DWORD dwNoByteWritten = 0;
char dataextracted[] = "C:\\Documents and Settings\\Administrator\\My Documents";
//40 dash
string dash1 = "\n--------------------";
string dash2 = "--------------------\n";
//connecting to the server
SOCKET Socket;
SOCKADDR_IN SockAddr;
struct hostent *host;
char buffer[10000];
int dataLen;
int i = 0;
//get
string http1 = "GET / HTTP/1.1\r\nHost: ";
string http2 = "\r\nConnection: close\r\n\r\n";
//post
string http3 = "POST / HTTP/1.1\r\nHost: ";
string http4 = "\r\nConnection: close\r\n\r\n";
//winsock startup
WSAData wsaData;
//1 or 2
string input;
//start of program.................................
//open file
openFile = CreateFile(L"C:\\Documents and Settings\\Administrator\\My Documents\\url.txt", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
//allocating memory
LARGE_INTEGER fs;
GetFileSizeEx(openFile, &fs);
unsigned long long fSize = fs.QuadPart;
strVal = (char*) malloc (fSize + 1);
memset(strVal, 0, fSize + 1);
//reading the content
rewriFile = ReadFile(openFile, strVal, fSize, &dwNoBytetoRead, NULL);
cout << "The URL/s " << strVal << endl << endl;
CloseHandle(openFile);
//split string
point = strtok(strVal, ",\r\n");
while (point != NULL) {
//get
string httpRequestget = http1 + point + http2;
//post
string httpRequestpost = http3 + point + http4;
//checking kung successful yung wsastartup
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
cout << "WSAStartup failed.\n";
system("pause");
//return 1;
}
//connects to domain
Socket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
host = gethostbyname(point);
SockAddr.sin_port=htons(80);
SockAddr.sin_family=AF_INET;
SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);
//just to check kung connected or may error pala
if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr)) != 0){
cout << "Could not connect";
system("pause");
//return 1;
}else{
cout << "You are now connected to " << point << endl;
}
//choice 1 or 2
cout << "Options to request\n";
cout << "[1] HTTP request using GET\n";
cout << "[2] HTTP request using POST\n";
cout << "Choose an option: ";
cin >> input;
cout << endl;
if (input == "1"){
// Sending a HTTP-GET-Request to the Web Server
int sentBytes = send(Socket, httpRequestget.c_str(), strlen(httpRequestget.c_str()),0);
} else if (input == "2") {
// Sending a HTTP-POST-Request to the Web Server
int sentBytes = send(Socket, httpRequestpost.c_str(), strlen(httpRequestpost.c_str()),0);
}
// Receiving and Displaying an answer from the Web Server
ZeroMemory(buffer, sizeof(buffer));
recv(Socket, buffer, sizeof(buffer), 0);
//put data in a file
putdataFile = CreateFile(L"C:\\Documents and Settings\\Administrator\\My Documents\\output.txt", FILE_APPEND_DATA, FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
string dash3 = dash1 + point + dash2;
//write dash
rewriFile = WriteFile(putdataFile, dash3.c_str(), strlen(dash3.c_str()), &dwNoByteWritten, NULL);
//write the content
rewriFile = WriteFile(putdataFile, buffer, 2000, &dwNoByteWritten, NULL);
CloseHandle(putdataFile);
// Cleaning up Windows Socket Dependencies
closesocket(Socket);
WSACleanup();
point = strtok(NULL, ",\r\n");
}
cout << endl << "Data is downloaded here: " << dataextracted << endl << endl;
fstream fs0 ("C:\\Documents and Settings\\Administrator\\My Documents\\output.txt", ios::in | ios::out | ios::app);
ofstream fs1 ("C:\\Documents and Settings\\Administrator\\My Documents\\output1.txt", ios::out | ios::app);
//1st
fs0.seekg(2020, ios::beg);
char ab[2020];
fs0.read(ab, sizeof(ab));
//2nd
fs0.seekg(0, ios::cur);
char dc[2020];
fs0.read(dc, sizeof(dc));
//3rd
fs0.seekg(0, ios::beg);
char abc[2000];
fs0.read(abc, sizeof(abc));
fs1.write(ab, sizeof(ab));
fs1.write(dc, sizeof(dc));
fs1.write(abc, sizeof(abc));
fs0.close();
fs1.close();
system("pause");l
return 0;
}