Fundamentals of Programming Constructs.pptx

Fundamentals
Programming
Constructs

Father of C
 C Programming was developed by Dennis Ritchie for
creating system applications that directly interact
with the hardware devices such as drivers, kernels,
etc.
 C programming is considered as the base for other
programming languages, that is why it is known as
mother language.

Features of C
MOTHER/SYSTEM/PRO
CEDURAL/STRUCTURE
D
MACHINE
DEPENDENT
RICH LIBRARIES DYNAMIC MEMORY
ALLOCATION

First C Program #include <stdio.h>
void main()
{
//Print a statement
printf(“Welcome");
}

How C Works
Output
Loader
• CPU
Linker
• Executable
code(.exe)
Compiler
• Obj codes(.o)
Preprocessor
• IncludeFiles
and replaced
Symbols
Editor or IDE
• Source
Code(.c) and
Header(.h)

Variable
A variable is a name of the
memory location.
It is used to store data.
Its value can be changed,
hence it is called a variable
Syntax:
datatype varName;
Eg: int no;

Rules for a
Variable
A variable can have alphabets, digits, and
underscore.
•A variable name can start with the
alphabet, and underscore only. It can't
start with a digit.
•No space is allowed within the variable
name.
•A variable name must not be any
reserved word or keyword, e.g. int, float,
etc

Variables
VALID
 int a;
 int _ab;
 int a30;
INVALID
 int 2;
 int simple interest;
 int float;

Variables
DECLARATION
 int a;  int a = 80;
INITIALISATION

Types of Variables
LOCAL GLOBAL STATIC AUTOMATIC EXTERNAL

Local Variable
DEFINITION
 A variable that is declared inside the
function or block is called a local
variable.
 It is available only for the function or
the block
 You must have to initialize the local
variable before it is used.
EXAMPLE
void main()
{
int x=10;//local variable
}

Automatic Variable
DEFINITION
 The variables which are declared inside a
block are known as automatic or local
variables;
 These variables allocates memory
automatically upon entry to that block and
free the occupied memory upon exit from that
block.
 We can explicitly declare an automatic
variable using auto keyword.
EXAMPLE
void main(){
int x=10;//local (also automatic)
auto int y=20;//automatic variable
}

Global Variable
DEFINITION
 A variable that is declared outside the
function or block is called a global
variable.
 Any function can change the value of
the global variable.
 It is available to all the functions.
EXAMPLE
int value=20;//global variable
void main()
{
}

Static Variable
DEFINITION
 A variable that is declared with the static
keyword is called static variable.
 It retains its value between multiple function
calls.
 The local variable will print the same value
for each function call, e.g, 11,11,11 and so on.
 But the static variable will print the
incremented value in each function call, e.g.
11, 12, 13 and so on.
EXAMPLE
void function1(){
static int y=10;//static variable
x=x+1;
y=y+1;
printf("%d,%d",x,y);
}

External Variable
DEFINITION
 We can share a variable in multiple C source
files by using an external variable.
 To declare an external variable, use extern
keyword.
EXAMPLE
extern int x=10;
//external variable (also global)

Datatype
 A data type specifies the type of data that a
variable can store such as number, character
or decimal etc.
 The basic data types are integer-based and
floating-point based.
 C language supports both signed and
unsigned literals.
 The memory size of the basic data types may
change according to 32 or 64-bit operating
system.

Datatype
int are whole numbers that can have both zero,
positive and negative values but no decimal values.
float and double and are used to hold real
numbers.
char is used for declaring character type variables
Void is an incomplete type. It means "nothing" or
"no type".
If you need to use a large/small number, you can
use a type specifier long/short

Signed and
unsigned
 In C, signed and unsigned are type modifiers.
You can alter the data storage of a data type
by using them. For example,
 unsigned int x;
 int y;
 Here, the variable x can hold only zero and
positive values because we have used the
unsigned modifier.
 Considering the size of int is 4 bytes, variable
y can hold values from -231 to 231-1, whereas
variable x can hold values from 0 to 232-1.

Data Types Memory Size Range
char 1 byte −128 to 127
signed char 1 byte −128 to 127
unsigned char 1 byte 0 to 255
short 2 byte −32,768 to 32,767
signed short 2 byte −32,768 to 32,767
unsigned short 2 byte 0 to 65,535
int 4 byte -2,147,483,648 to 2,147,483,647
signed int 2 byte −32,768 to 32,767
unsigned int 4 byte 0 to 4,294,967,295
short int 2 byte −32,768 to 32,767
signed short int 2 byte −32,768 to 32,767
unsigned short int 2 byte 0 to 65,535
long int 4 byte -2,147,483,648 to 2,147,483,647
signed long int 4 byte -2,147,483,648 to 2,147,483,647
unsigned long int 4 byte 0 to 4,294,967,295
float 4 byte
double 8 byte
long double 10 byte

printf()
scanf()
The printf() function is used for printing
output to the console.
The scanf() function is used for reading
input data from the console.
The format string can be %d (integer)etc
1.scanf("%d",&x);
printf("sum of 2 numbers:%d ",result);
Syntax:
printf("format string",argument_list);
scanf("format string",&argument);

Format
Specifier
Type Format Specifier
int %d.%i
unsigned int %u
short int %hd
long int %ld, %li
unsigned long int %lu
char %c
signed char %c
unsigned char %c
float %f
double %lf
long double %Lf
The Format specifier determines the
format of the input and output.
The format string always starts with a '%'
character.

Now that was
a lot of
theory!!!
Let's do some
coding

#include<stdio.h>
void main()
{
int no1,no2;
int sum=0;
printf("Enter no1");
scanf("%d",&no1);
printf("Enter no2");
scanf("%d",&no2);
sum = no1+no2;
printf("The sum is %d",sum);
}
Let's convert the flowchart
to a program in C

#include<stdio.h>
void main()
{
int principal,time,rate;
float simpleInterest;
printf("Enter p,n,r");
scanf("%d%d%d",& principal,& time,& rate);
simpleInterest =(principal * time * rate)/100;
printf("The sum is %f", simpleInterest);
}
Program 2

 import
Good! Try one More!

 Write an algorithm for converting Celsius to Fahrenheit
 Draw a flowchart
 And covert it into a Code in C
 T(°F) = T(°C) × 1.8 + 32
Great Going! Now Try all 3 together!

Fundamentals of Programming Constructs.pptx

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