Methods to Open File,

• The second argument of fopen is the mode in which we open the file.   
• "r" opens a file for reading.
• “r+” opens a file for both reading & writing.
• "w" opens a file for writing - (deletes the existing file of same name).
• “w+” for both reading & writing.
• "a" opens a file for appending - writing on the end of the file.
• “a+” for both reading & appending.