C Programming Tutorial

Computer Tutorial

Introduction & History of C Constants & there Types Variables & there Types C Keywords Data Type in C C - Operators First Program in C

Decision Control Statements The if statement Multiple if statement The if-else statement Ternary operator ( ? ) goto statement switch statement

Loops in C The While loop The do-while loop The for loop Nesting of Loops Break & Continue Statement

Array in C Declaration of an Array Entering Data into an Array Reading Data from an Array Array Elements in Memory Passing Array Elements to a Function Passing an Entire Array to a Function Two-Dimensional Arrays Initialising a 2-D Array Reading Data from 2-D Array Memory Map of 2-D Array Three-Dimensional Array

Pointer in C Pointer Variables Declaration Pointer Operators

String in C Pointers and Strings String Functions strlen( ) Function strcpy( ) Function strcat( ) Function strcmp( ) Function

Function in C Function Prototypes declaration Call by Value Call by Reference Returning Values Recursion

Structure in C Declaring a Structure Accessing Structure Members Structure Assignments Arrays of Structures Passing Structures to Functions Structure Pointers Uses of Structures

Union in C Difference Between Structure and Union

» File Handling in C » File Operations » Opening a File » Reading from a File » Trouble in Opening a File » Closing the File » Writing to a File » File Opening Modes » File Handling Functions

Additional Tutorials on C

Objective Question on C

File Opening Modes

File Opening Modes

All possible modes in which a file can be opened. The tasks performed by fopen( ) when a file is opened in each of these modes are also mentioned.

" r "	Searches file. If the file is opened successfully fopen( ) loads it into memory and sets up a pointer which points to the first character in it. If the file cannot be opened fopen( ) returns NULL. Operations possible – reading from the file.
" w "	Searches file. If the file exists, its contents are overwritten. If the file doesn’t exist, a new file is created. Returns NULL, if unable to open file. Operations possible – writing to the file.
" a "	Searches file. If the file is opened successfully fopen( ) loads it into memory and sets up a pointer that points to the last character in it. If the file doesn’t exist, a new file is created. Returns NULL, if unable to open file. Operations possible - adding new contents at the end of file.
" r+ "	Searches file. If is opened successfully fopen( ) loads it into memory and sets up a pointer which points to the first character in it. Returns NULL, if unable to open the file. Operations possible - reading existing contents, writing new contents, modifying existing contents of the file.
" w+ "	Searches file. If the file exists, its contents are overwritten. If the file doesn’t exist a new file is created. Returns NULL, if unable to open file. Operations possible - writing new contents, reading them back and modifying existing contents of the file.
" a+ "	Searches file. If the file is opened successfully fopen( ) loads it into memory and sets up a pointer which points to the first character in it. If the file doesn’t exist, a new file is created. Returns NULL, if unable to open file. Operations possible - reading existing contents, appending new contents to end of file. Cannot modify existing contents.

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