INPR

• Input


  To send information to a computer for processing
• Output


  To display information or results after processing
• File


  A collection of data stored in one unit, identified by a filename
• How to Open a File

  1. File Pointer

  2. Fopen - Fclose
• File Pointer


  Initializes an object of the type FILE, which contains all the information necessary to control the stream
• Fopen - Fclose


  FILE *fp;

  FILE *fopen( const char * filename, const char * mode );

  fp = fopen("fileName", "w");
• fprintf()


  Function used to write set of characters into file. Sends formatted output to a stream.
• fscanf()


  Function used to read set of characters from file. Reads a word from the file and returns EOF at the end of file.
• fputc()


  Function used to write a single character into file. Outputs a character to a stream.
• fgetc()


  Function returns a single character from the file. Gets a character from the stream. Returns EOF at the end of file.
• fputs()


  Function writes a line of characters into file. Outputs string to a stream.
• Exception handling is designed to process synchronous errors, which occur when a statement executes
• Exception handling is not designed to process errors associated with asynchronous events
• Classic 'C' Approach to EXCEPTION handling

  Each function returns a value indicating success or failure

  Every function must check the return code of every function call it makes and take care of errors

  Exceptions make it easy to separate error handling from the rest of the code
• Methods of EXCEPTION Handling

  If-else method

  setjmp() and longjmp()
• If-else method


  Exception is handled by making decisions via if – else

  Occurrence of an exception is checked by the return values of a function or by defined parameters

  Along with that condition is placed an if – else statement that checks and performs the respective action against that exception
• setjmp() and longjmp()


  Used to jump away from a particular location in a program into another function

  The programmer written code, inside that function handles the exception

  To test the occurrence of an exception the setjmp() functions is called up

  Setjmp() saves the most recent event of the program before that statement in a buffer called jmp buff

  As soon as the exception test is complete the setjmp() returns a value to the function

  If the value returned from the setjmp() to the longjmp() is '0' it means that there was an exception condition

  Now the program will start again from the same point where it stopped (saves in the buffer), until the exception condition is removed or repaired