1.
Command-line:
- It describes what's going on inside a program, so that person looking at the source code does not have a hard time figuring it out.
Types
of comments:
(i)Single
line comments:
Syntax:
/*Statements*/
Example:
/* This is the addition program*/
(ii)Multiline comments:
Syntax:
//Statement
2.Variables:
- A variable is nothing but it allocates the memory space and holds the values.
Syntax:
Data_type variable_name;
Example:
int x, y;
Rules
for naming the variables:
- The first character must be an alphabet or an underscore(_).
- No commas or blank spaces are allowed within a variable name.
- No special symbols, an underscore can be used in a variable name.
User
defined variables:
a).
Type declaration:
- It is used to allow the user to define an identifier that would represent an existing data type.
Syntax:
typedef data_type identifier;
Example:
typedef int marks;
marks m1,m2,m3;
b).
Enumerated data type:
- It is used to create user-defined data types i.e. the programmer can create their own data type and define what values the variables of those data types can hold.
Syntax:
enum enum
_name{value 1,value 2, ......,value n};
Example:
enum day{mon,tue,wed,...sun};
Scope
of variables:
- It implies the availability of variables within the program.
- It is divided into two types.
1).
Local variable:
- The variables which are defined inside the function block called a local variable.
Example:
void main()
{
int a,b;//local
variable
......
}
2).
Global variable:
- The variables that are declared before the main() function is called a global variable.
Example:
int a,b;//Global
variable
void main()
{
......
}
3.Data
types:
- It means kinds of data that means numbers or words.
- The most widely used data types are
1. int (integer) - real numbers
Ex: 1, 2, -5, 1311
2. float - decimal number:
Ex: 1.45, 0.001
3. char(character)- Alphabets
Ex: k,f,v,h
4.double – combinations of int and float numbers
Ex: 1.001,89,1654
4. Input
function:
- This function is used to value get from users.
Syntax:
scanf(“ format specifiers ”,variable_name);
Example:
scanf("%d",z);
Example:
scanf("%d",z);
5.Format
specifiers:
- It is used to indicate unknown value for types to display on the output screen and also get value from user. ( i.e. Holds unknown values)
There are,
6.Output
function:
- This function is used to show details for users.
Syntax:
printf(“Statements”);
Example:
printf("Welcome to whereisstuff");
Example:
printf("Welcome to whereisstuff");
7.Escape
sequence:
- This is used for aligning output on the screen.
Escape
sequence
|
Description
|
Example
|
Output
|
\n
|
Newline or next line
|
printf(“Hai! \n I am
Sabrina.”)
|
Hai! I am Sabrina.
|
\t
|
Horizontal tab(one
tab space)
|
printf(“Hai\t Hello”)
|
Hai hello
|
\’
|
Display single-quotes
|
printf(“I don\”t
know”)
|
I don’t know
|
\”
|
Display double-quotes
|
printf(“/“Hey/”’)
|
“Hey”
|
\\
|
Print slash
|
printf(“a//b”)
|
a/b
|
/* To print "Welcome to whereisstuff " and multiply two numbers */
/* To print "Welcome to whereisstuff " and multiply two numbers */
#include<stdio.h>
#include<conio.h>//header files
void main()//main function
{
int x,y,z;//variable-declaration
clrscr();
printf("Welcome to whereisstuff\t\n Multiply two numbers\n");//print fun
printf("Enter x and y value:\n");
scanf("%d%d",&x,&y);//get value from user and store
z=x*y;
printf("Multiply value is: %d",z);//result disply
getch();
}
