This is a C basic program Sum of two numbers: Let us see about each section of a C basic program in detail below. Sections Description Documentation section We can give comments about the program, creation or modified date, author name etc in this section.
This has to do with consistency, a consistent system where different modules do things in a similar manner will be much easier to understand than a system where each module does things in a different manner. If you get astonished by what a function does, either your function solves the wrong problem or it has a wrong name.
Erlang has several primitives which have side effects. Functions which use these cannot be easily re-used since they cause permanent changes to their environment and you have to know the exact state of the process before calling such routines. Write as much as possible of the code with side-effect free code.
Maximize the number of pure functions. Collect together the functions which have side effect and clearly document all the side effects. With a little care most code can be written in a side-effect free manner - this will make the system a lot easier to maintain, test and understand.
This is best illustrated by a simple example. We define a simple module called queue - to implement queues: This implements a queue as a list, unfortunately to use this the user must know that the queue is represented as a list.
A typical program to use this might contain the following code fragment: This is bad - since the user a needs to know that the queue is represented as a list and b the implementer cannot change the internal representation of the queue this they might want to do later to provide a better version of the module.
Now we can write: Which is much better and corrects this problem. Now suppose the user needs to know the length of the queue, they might be tempted to write: Again this is bad programming practice and leads to code which is very difficult to maintain and understand.
If they need to know the length of the queue then a length function must be added to the module, thus: Now the user can call queue: Here we say that we have "abstracted out" all the details of the queue the queue is in fact what is called an "abstract data type".
Why do we go to all this trouble? So, for example, a better implementation of the queue is as follows: A non-deterministic program may deliver different results each time it is run.
For debugging purposes it is a good idea to make things as deterministic as possible. This helps make errors reproducible.
For example, suppose one process has to start five parallel processes and then check that they have started correctly, suppose further that the order in which these five are started does not matter. We could then choose to either start all five in parallel and then check that they have all started correctly but it would be better to start them one at a time and check that each one has started correctly before starting the next one.
In general one should not test input data to functions for correctness. Most of the code in the system should be written with the assumption that the input data to the function in question is correct.
Only a small part of the code should actually perform any checking of the data.
This is usually done when data "enters" the system for the first time, once data has been checked as it enters the system it should thereafter be assumed correct. The function will crash if Option neither normal nor all, and it should do that. The caller is responsible for supplying correct input. The device drivers should implement hardware interfaces which make the hardware appear as if they were Erlang processes.
Hardware should be made to look and behave like normal Erlang processes. Hardware should appear to receive and send normal Erlang messages and should respond in the conventional manner when errors occur. Suppose we have a program which opens a file, does something with it and closes it later.Read/Write structure to a file in C Prerequisite: Structure in C For writing in file, it is easy to write string or int to file using fprintf and putc, but you might have faced difficulty when writing contents of struct.
C Program Structure - Free tutorial and references for ANSI C Programming. You will learn ISO GNU K and R C99 C Programming computer language in easy steps. C is the most popular system programming and widely used computer language in the computer world. C nested structure.
Previous Page. Next Page. Structure within Structure: Nested Structure. Structure written inside another structure is called as nesting of two structures.
Nested Structures are allowed in C Programming Language. We can write one Structure inside another structure as. C Program Write a Program to Sum of N Number. C Program Using Structure to Calculate Marks of 10 Students in Different Subjects.
Structure in C programming with examples By Chaitanya Singh | Filed Under: c-programming Structure is a group of variables of different data . I guess, if that's the case there should be a structure for the file, for example, let's say you write the type in one line and the object in another line etc..
then from the program based on the type you can know the size..
– pinkpanther Mar 27 '17 at