My Coding!: C programming
Showing posts with label C programming. Show all posts
Showing posts with label C programming. Show all posts

Tuesday 3 February 2015

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How to start the real program ?



Hi guys

Let's start the real program

Eaxample 1:
#include <stdio.h>
void main()
{
   clrscr();
   printf("\n Hello world")
   getch();
}
Explanation : In above program #include is a preprocesser, it is predefined directory. "stdio.h" is a header file which means standard input output, it is a header file which defines input output operation.

The function clrscr() clear the screen. In c program , when the program is execute it also display the previous output of program. So whenever you execute you have to clear it before the execution of new program.

The function getch() is used to hold the screen. It is mostly use with Turbo C. But if you have advance version like C free , you don't need to write it.

Example 2:
Take the input from user and to display it.
#include <stdio.h>
void main()
{
 int  x ;
clrscr();
printf("\nEnter a number : ")
scanf("%d ", &x);
 printf("\nYour number is %d : ", x )
getch();
}
Explanation :-  The printf() function is used to display the item.
scanf () function is used to store the values.




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Scope of Variables And Range of Datatypes



Hi guys ,
In last post we learnt about how to declare the variable and when it declare, today we learnt about what are the scope and range of  variable types so let's start :
Scope of variables
Scope of the variable means life of variable. The scope of variable is limited to the function where it declare. Let's take an example
#include <stdio.h>
void main()
{
  int x;
 x=5;
printf("\n  Value of x is 5");
}
In above program the scope of the variable is inside the main function, if we want to access the variable outside the main function it is not accessible because it's scope is finished after "}" .

Range of the variable types or data types
following is the range of the various datatypes


Note : The size and ranges of int, short and long are compiler dependent. Size in this table are of 16 bit compiler.
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Sunday 1 February 2015

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Program Explanation


Hi Friend , Thanks to coming once again


In any programming it’s very important to explain your code not only for you but also other who are interested in your code. So, in any programming language you can explain your code using COMMENTS. Comments are critical for all but the most trivial programs and this tutorial will often use them to explain sections of code. When you tell the compiler a section of text is a comment, it will ignore it when running the code, allowing you to use any text you want to describe the real code. To create a comment in C, you enter the text with /* and then */ to block off everything between as a comment. Certain compiler environments or text editors will change the color of a commented area to make it easier to spot, but some will not. Be certain not to accidentally comment out code (that is, to tell the compiler part of your code is a comment) you need for the program. When you are learning to program, it is also useful to comment out sections of code in order to see how the output is affected.

So let’s start the programming

Variables

Many times you need to interact with the user, it means that need to take input from user, but before you take input you have a place to store it. The variables are nothing but the name of place in memory where the input data is stored. There are several different types of variables; w hen you tell the compiler you are declaring a variable, you must include the data type along with the name of the variable. Several basic types include char, int, and float. Each type can store different types of data.


A variable of type char stores a single character, variables of  type int store integers (numbers without decimal places), and variables of type float store numbers with decimal places. Each of these variable types - char, int, and float - is each a key word that you use w hen you declare a  variable. Some variables also use more of the computer's memory to store their values.

It may seem strange to have multiple variable types when it seems like some variable types are redundant. But using the right variable size can be important for making your program efficient because some variables require more memory than others. For now, suffice it to say that the different variable types will almost all be used! 

Before you can use a variable, you must tell the compiler about it by declaring it and telling the compiler about what its "type" is. To declare a variable you use the syntax <variable type> <name of variable>;. (The brackets here indicate that your replace the expression with text described within the brackets.) For instance, a basic variable declaration might look like this:

int myvariable

Note once again the use of a semicolon at the end of the line. Even though we're not calling a function, a semicolon is still required at the end of the "expression". This code would create a variable called myVariable; now we are free to use myVariable later in the program. 

It is permissible to declare multiple variables of the same type on the same line; each one should be separated by a comma. If you attempt to use an undefined variable, your program will not run, and you will receive an error message informing you that you have made a mistake. 

Here are some variable declaration examples:

int x;
int a,b,c;
char letter
float the_float

While you can have multiple variables of the same type, you cannot have multiple variables with the same name. Moreover, you cannot have variables and functions with the same name. 

A final restriction on variables is that variable declarations must come before other types of statements in the given "code block" (a code block is just a segment of code surrounded by { and }). So in C you must declare all of your variables before you do anything else: 
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Friday 23 January 2015

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Basics of C Programming



This article is designed to be a stand-alone introduction to C, even if you've never programmed before.  I recommend the C, for people who have never programmed before. Because C is simple programming language and understandable to anyone.So Let's Start...



Getting set up - finding a C compiler


The very first thing you need to do, before starting out in C, is to make sure that you have a compiler. What is a compiler? A compiler turns the program that you write into an executable that your computer can actually understand and run. It means that the program which you write is in human understandable language known as source code, but machine doe's not understand this language, machine understand only binary language 1, 0. Compiler is the system software which convert source code into executable file.
If you don't have Compiler don't worry you can download it from following link... 

Download C Compiler + IDE

Sample Program

#include <stdio.h>

main()

{
  clrscr();
  printf("Hello World");
  getch();
}


Intro to C

Every full C program begins inside a function called "main”.  A function is simply a collection of commands that do "something". The main function is always called when the program first executes. From main, we can call other functions, whether they be written by us or by others or use built-in language features. To access the standard functions that comes with your compiler, you need to include a header with the #include directive. What this does is effectively take everything in the header and paste it into y our program. Let's look at a working program :

Let's look at the elements of the program. The #include is a "preprocessor" directive that tells the compiler to put code from the header called “stdio.h” into our program before actually creating the executable. By including header files, you can gain access to many different functions--both the “printf” and “getchar” functions are included in “stdio.h”. The next important line is int main(). This line tells the compiler that there is a function named main, and that the function returns an integer, hence int. The "curly braces" ({ and }) signal the beginning and end of functions and other code blocks. If  you have programmed in Pascal, you will know them as BEGIN and END. Even if you haven't programmed in Pascal, this is a good w ay to think about their meaning. The “printf” function is the standard C w ay of displaying output on the screen. The quotes tell the compiler that you want to output the literal string as-is (almost). The '\n' sequence is actually treated as a single character that stands for a new line (we'll talk about this later in m ore detail); for the time being, just remember that there are a few sequences that, w hen they appear in a string literal, are actually not displayed literally by “printf” and that '\n'  is one of them . The actual effect of  '\n'  is to move the cursor on y our screen to the next line. Notice the semicolon: it tells the compiler that you're at the end of a com m and, such as a function call. You w ill see that the semicolon is used to end m any lines in C. The next com m and is  “getchar()”. This is another function call: it reads in a single character and waits for the user to hit enter before reading the character. This line is included because many compiler environments will open a new console window, run the program , and then close the window before you can see the output. This com m and keeps that window from closing because the program is not done yet because it waits for you to hit enter. Including that line gives you time to see the program run. Finally, at the end of the program, we return a value from main to the operating system by using the return statement. This return value is important as it can be used to tell the operating system whether our program succeeded or not. A return value of 0 means success.


The final brace closes off the function. You should try com piling this program and running it. You can cut and paste the code into a file, save it as a c file, and then com pile it. If you are using a com m and-line compiler, such as Borland C+ + 5.5, you should read the compiler instructions for information on how to com pile. Otherwise com piling and running should be as simple as clicking a button with y our mouse (perhaps the "build" or "run" button). You might start playing around with the “printf” function and get used to writing simple C programs.

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