For Beginners In C

Hello All Visitors and Members!
Here, I'm going to start a small "Short Note" series for beginners! Means, here I'm going to describe all C items step by step! Such as why should we use

or what is the purpose of

 

#include<xxx.h>

What Is #?
# denotes preprocessor, in simple word, it gives instruction to the compiler to compile those lines first who are started with #.

What is a .h file?
A .h file is called header file. It contains some definitions or codes of some functions which are usually used in every program. Such as, if you do not give the line

then your compiler will give error if you have used

So, #include<xxx.h> is used to include some codes to your programs, which are predefined!

Information:

Basically used to use scanf or printf.

Basically used for getch();

Basically used for some mathematical functions, e.g, sqrt etc.

 

Nice topic started!

 

Thank U techinspiration!

 

printf(); and scanf();
printf is usually used to display something in the terminal or screen!
syntax-

Code:

printf("Target Word");
and
printf("%d",xxx);

the second term is used to display any integer or float or whatever!
[hr]
scanf is usually used to take inputs from user!
syntax-

Code:

scanf("%d",&xxx);

the %d can be replaced by %f for floating point values, %c for characters etc.

 

getch();
this is used in old C compilers, this is used to hold the results on the terminal widow! If you forget to give it, then after compiling and calculating the whole result, the terminal will go off without showing the result.
syntax:

Code:

getch();

should be used before the closing bracket of

Code:

void main()
{
........
........
getch();
}

 

if - else
if - else condition is generally used for a single condition checking statements. Such as if x=2 then you have to add 1 with y else add 2 with y etc.
So how to write the statement?

Code:

if(x=2)
{
z=y+1;
printf("%d",z);
}
else
{
z=y+2;
printf("%d",z);
}

in addition to this, when you have single statement in if or in else section then its not necessary to give the brackets {}.

 

I would like to add SWITCH - CASE to this:
What is it?
This is used to declare many conditions, such as

etc.

syntax

Code:

switch(x)
default:
[i]statement[/i]
break;
case 1:
[i]statement[/i]
break;

case 2:
[i]statement[/i]
break;

case 3:
[i]statement[/i]
break;

 

hi techinspiration!
what you have posted is right but needs to be cleared with an example-
Here is ti:

Code:

...
int choice;
...
scanf("%d",&choice);
switch(choice)
default:
printf("Wrong Entry!!!"):
case 1:
if(x>10)
  y=x+2;
else
  y=x+5;
printf("%d",y);
break;

case 2:
if(x<10)
  y=x+10;
printf("%d",y);
break;

Hope this will help more to understand the SWITCH - CASE

 

do - while
This is usually used to do some operation first and then to check a condition, such as

Code:

do
{
scanf("%d",&x);
y=x+2;
}
while(y>3)

means compiler will execute the code again if the ans i.e, y is greater than 3.

Syntax:

Code:

do
{
statement;
}
while(argument)

 

WHILE loop
syntax:

Code:

while(condition)
{
statement
}

This loop is also called Entry Controlled loop. This is usually used to make such sections where a particular is to be compared with another.
Suppose, you given that
input a value x, then add 1 with y (another integer) until x reaches to 10. for this type of arguments we can use while loop.
Example:

Code:

while(x<11)
{
y=y+1;
x++;
}

This is the solution of the above problem!