Question

how to login a website using c ?? harvard cs50 question

Answer 1

You mean submit POST/GET data to a webserver?

Try getting used to logging in over telnet/netcat first, then implement that in C with sockets/winsock/SDLnet.

Connect to the webserver on port 80, send the get/post request and read the response.

Answer 2

can you tell me the name of the header file to implement these ,pls ?

Answer 3

if possible please tell me some nice book about socket programming in c

Answer 4

The best book that I know of for socket programming is "Unix Network Programming" by Stevens.

A good free tutorial for socket programming is http://beej.us/guide/bgnet/output/html/singlepage/bgnet.html

If you just need to "get something done" You might investigate using "libcurl"
http://curl.haxx.se/libcurl/c/
Libcurl can be used to fetch web pages and post data to web-servers. I takes care of the tedious HTML protocol stuff for you.