Corrected errors and changed reading from file.

1. Changed minor errors;
2. Changed remove() into remove_car() function;
3. Changed the way a file is read.
Renamed function and comment added.

1. Renamed remove() -> remove_car();
2. Added and edited some comments.
Added some includes + minor corrections.

1. Added includes for strcmp, srand, rand;
2. Renamed the changed functions, like remove -> remove_car();
3. Added srand(time(NULL)) before using rand().