C read from console and write to .txt file -

How can I read a lesson written in the console and enter it in the text file until the user Do not end ?? I have written it but the problem is that when I type I do not close it.

  int _tmain (int argc, _TCHAR * argv []) {FILE * fp; Four sentences [80]; Fp = fopen ("C: \\ users \\ costa \\ desktop \\ original.txt", "w"); While (sentence! = "Exit") (becomes); Fputs (sentence, fp); } Return 0; }    
 
 
 change it: -  
  while ( (Strcmp (sentence, "exit")! = 0)    
 to  
 >  < / Html>