Zaridah lecture2

ZMZ JANUARY 2012

PROGRAMMING 1
BEB14103

Lecture 1
1

DATA TYPES
Topic Outcomes
• The students are able to identify four
standard types of data in C
• The students are able to declare the
variables according to the data types
• The students are able to create C
programs with various of data types

2

INTRODUCTION
Data
types

int float char void

There are four basic data types :
• Int
• Float
• Char
• Void

3

INTEGER

• Integer is number without the fraction part
• Support three different sizes (1 byte, 2
bytes and 4 bytes)
• An integer constant must have at least
one digit
4

CONT..
• It must not have a decimal point
• It can be either positive or negative
• If no sign precedes an integer
constant it is assumed to be positive
• No commas or blanks are allowed
within an integer constant
• Examples :

426 +782 -8000 -7605
5

CHAR
• The letters of the alphabet
• Most computers use the American Standard
Code for Information Interchange (ASCII)
• The maximum length of a character constant
can be 1 character
• Examples :
• 'A'
• 'I'
• '5'
• '='

6

FLOAT

• Number with a fractional part, such as 43.32
• Support three different sizes of floating point data types: float,
double and long double
• Double provides twice the precision of float
• Floats typically take up 4 bytes
• Doubles takes up 8 bytes
• Long double takes 10 bytes
7

VOID
• The void type has no values therefore we cannot
declare it as variable as we did in case of integer
and float.
• The void data type is usually used with function
to specify its type.
• Like in in the first C program we declared
“main()” as void type because it does not return
any value.

8

RANGE OF DATA TYPES IN C

9

VARIABLES
• Variables are named memory
locations that have a type.
• Must be declared and defined
• Declaration is used to name an
object such as a variable
• Definitions are used to create the
object
• A variable cannot be type void
10

CONT..
In order to use a variable in our program we must first
declare it

HOW? A declaration statement has the following format:

type variable name;
–type : what kind of data will be stored in that location
(integer?character? floating point?)
–variable name: what is the name of the variable?
–semi-colon : indicates this is a statement!

int num_students; // declaration
num_students= 22; // initialization
12

EXAMPLE 2.1
#include <stdio.h>
main()
{
int num1, num2, sum;
printf(“Enter one decimal number:”);
scanf(“%d”, &num1);
printf(“Enter another decimal number:”);
scanf(“%d”, &num2);
sum = num1 + num2;
printf(“nSum of %d and %d is %d ”, num1, num2, sum);
return 0;
}
13

EXAMPLE 2.2
#include <stdio.h>
main()
{
float area_rectangle, width, length;
printf(“Enter the length:”);
scanf(“%f”, &length);
printf(“Enter the width:”);
scanf(“%f”, &width);
area_rectangle = length * width;
printf(“nArea of the rectangular is %f ”, area_rectangle);
return 0;
}
14

EXAMPLE 2.3
#include <stdio.h>
main()
{
double pi, height, radius, base, volume;
pi = 3.142;
printf(“Enter the height the cone:”);
scanf(“%lf”, &height);
printf(“Enter the radius of the cone:”);
scanf(“%lf”, &radius);
base = pi * radius * radius;
volume = (1.0/3.0) * base * height;
printf(“nThe volume of a cone is %f ”, volume);
return 0;
}

15

#define
/*You may also associate constant using #define preprocessor directive*/
#include <stdio.h>
#define pi 3.142
main()
{
double height, radius, base, volume;
printf(“Enter the height the cone:”);
scanf(“%lf”, &height);
printf(“Enter the radius of the cone:”);
scanf(“%lf”, &radius);
base = pi * radius * radius;
volume = (1.0/3.0) * base * height;
printf(“nThe volume of a cone is %f ”, volume);
return 0;
}
16

EXAMPLE 2.4
#include <stdio.h>

main()
{
char Letter;
Letter = 'x';
printf(“nThe letter is %c ”, Letter);
return 0;
}

17

STANDARD OUTPUT
• printf Function
• prints information to the screen
• requires two arguments
• control string
• conversion specifier

Example
• double angle = 45.5;
• printf(“Angle = %.2f degrees n”, angle);

Output:
• Angle = 45.50 degrees

STANDARD INPUT
• scanf Function
• inputs values from the keyboard
• required arguments
• control string
• memory locations that correspond to
the specifiers in the control string

Example:

• double distance;
• scanf("%lf", &distance);

SUMMARY
• There are four standard data types can be use in
C program which are:
• Integer
• Float
• Char
• Void
• Everytime you want to use a variable, the
declaration must be made
• To associate the variables with the data types,
you can use standard input and output function

20

REFERENCE
Hanly, J. R. & Koffman, E. B (2001). C
Program Design for Engineers. Addison
Wesley Longman.

Deitel, P & Deitel H (2008). C How to
Program. Pearson Education Inc.

21

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