Which of the following is not a valid mode to open a file ?

1. ab
2. rw
3. r+
4. w+

Which of the following mode in file opening statement results or generates an error if the file does not exist ?

1. a+
2. r+
3. w+
4. None of these

Which of the following statements are true regarding the opening modes of a file ?

1. When you open a file for reading, if the file does not exist, an error occurs.
2. When you open a file for writing, if the file does not exist, an error occurs.
3. When you open a file for reading, if the file does not exist, the program will open an empty file.
4. When you open a file for writing, if the file does not exist, a new file is created.
5. When you open a file for writing, if the file exists, the existing file is overwritten with the new file.

Which of the following command is used to open a file "c:\pat.txt" for writing in binary format only ?

1. fout = open("c:\pat.txt", "w")
2. fout = open("c:\\pat.txt", "wb")
3. fout = open("c:\pat.txt", "w+")
4. fout = open("c:\\pat.txt", "wb+")