Month: May 2006

C Language – The Preprocessor In this tutorial you will learn about C Language – The Preprocessor, Preprocessor directives, Macros, #define identifier string, Simple macro substitution, Macros as arguments, Nesting of macros, Undefining a macro and File inclusion. The Preprocessor A unique feature of c language is the preprocessor. A program can use the tools provided by preprocessor to make his program easy to read, modify, portable and more efficient. Preprocessor is a program that processes the code before it passes through the compiler. It operates under the control of… Read More

C Programming – File management in C In this tutorial you will learn about C Programming – File management in C, File operation functions in C, Defining and opening a file, Closing a file, The getw and putw functions, The fprintf & fscanf functions, Random access to files and fseek function. C supports a number of functions that have the ability to perform basic file operations, which include: 1. Naming a file 2. Opening a file 3. Reading from a file 4. Writing data into a file 5. Closing a… Read More

In this tutorial you will learn about C Programming – Linked Lists, Structure, Advantages of Linked List, and Types of linked list and Applications of linked lists. Linked lists are a type of data structure for storing information as a list. They are a memory efficient alternative to arrays because the size of the list is only ever as large as the data. Plus they do not have to shift data and recopy when resizing as dynamic arrays do. They do have the extra overhead of 1 or 2 pointers… Read More

Embedded and other low-memory footprint applications need to be easy on the amount of memory they use when executing.  In such scenarios, statically sized data types and data structures just are not going to solve your problem.  The best way to achieve this is by allocation of memory for variables at runtime under your watchful eye. This way your program is not using more memory than it has to at any given time. However, it is important to note that the amount of memory that can be allocated by a call… Read More

Pointers are widely used in programming; they are used to refer to memory location of another variable without using variable identifier itself. They are mainly used in linked lists and call by reference functions. Diagram 1 illustrates the idea of pointers. As you can see below; Yptr is pointing to memory address 100. Diagram 1: 1. Pointer and memory relationship Pointer Declaration Declaring pointers can be very confusing and difficult at times (working with structures and pointer to pointers). To declare pointer variable we need to use * operator (indirection/dereferencing… Read More

In this tutorial you will learn about C Programming – Structures and Unions, initializing structure, assigning values to members, functions and structures, passing structure to functions, passing entire function to functions, arrays of structure, structure within a structure and union. Structures are slightly different from the variable types you have been using till now. Structures are data types by themselves. When you define a structure or union, you are creating a custom data type. Structures Structures in C are used to encapsulate, or group together different data into one object.… Read More

The concept of functions in C language is the same as for any other programming language. Few languages have methods but, since there are no classes in C, methods are not used. Functions are best used for reusable code, or code that you know works and do want make use of it throughout development. If you find yourself tempted to use copy and paste on a particular block of code, even once, then you should move the code into a function. Lets talk about the different types of variables before… Read More

Types of Functions You may have noticed the discussion about the <data type> portion of the function declaration missing from the last section. The <data type> refers to the type of data that would be returned by the function when it finishes executing. Data types are the same as any variable data types plus another one called void. Void type functions do not return any values. Function with no arguments and no return value: void function_name(); Think of this as a self-contained block of reusable code that does not need… Read More