BIC 10303 ALG

CHAP 3: STRUCTURE OF PROGRAMMING

Chapter : 3

3. EXPRESSIONS

AND OPERATIONS

Arithmetic operation

Relational operation

Assignment operation

Conditional operation

To give understanding on:

Expression and operator concept

math.h and stdlib.h built-in function

Students should be able to:

understand concepts and fundamentals in

expression/ operator.

write expression in C programming language

Objective

Aim

3

Given the following statement :

2x + 3 – z = y

expression

Introduction to Expression

Example:

Process involves in money withdrawal

scenario

balance – drew out money = current balance

Expression in C :

bakiTerkini =wangKeluar – bakiSemasa;

4 What is Expression?

ExpressionCombination of more than one variable or constant

(operand) which separated by operator

x + 3 - z

Operand

Operatorexample

Consists of arithmetic

relational

logical

Introduction to Expression

5

Arithmetic Expression Mathematic ExpressionKnown as

usingArithmetic Operator

Unary operator Binary operator

Represents by

Operator Meaning

- negative

+ positive

-- decrement

++ increment

Represents by

Operator Meaning* multiply

/ divide

+ add

- subtraction

% modulus

Arithmetic Expression

6 Unary Operator

Unary Operator Operates for one operand

example

a = -20; a -20

Computer memory cell

b = +15; b +15

Increment Decrement

prefix ++c; --c;

postfix c++; c--;

Arithmetic Expression

7 Unary OperatorExample 1:

int A = 5;

++A;

printf(“%d”, A); output ?

A--;

printf(“%d”,A); output ?

A++;

printf(“%d”,A); output ?

Arithmetic Expression

8 Unary Operator

Example 2:

int A ;

A=6;

printf(“%d”,3 + --A); output ?

printf(“%d”, A); output ?

A=6;

printf(“%d”, 3 + A--); output ?

printf(“%d”, A); output ?

Arithmetic Expression

9 Unary Operator

Example 3:

Given the value of num1 = 8 .Determine the value of num2 after the execution

for each of the following statements:

num2 = num1++ - 2;

num2 = num1;

num2 = ++num1 – 3;

num2 = num1-- +1;

Arithmetic Expression

10 Binary Operator

Binary OperatorLocated between constants or

variables or both combination

example

A + z

operator

operand

Arithmetic Expression

11 Binary Operator

Multiplication Use symbol “ * ”

exampleA * z

operator

operand

Mathematic

2x + y

Arithmetic Expression

2 * x + y

Arithmetic Expression

12

Binary Operator

Divide Use symbol “/”

exampleA / z

operator

operand

Mathematic

2 ÷ y

Arithmetic Expression

2 / y

Arithmetic Expression

13 Binary Operator

Modulus Use symbol “%”

exampleA % z

operator

operand

Return a balance when 2 numbers is divided

Can only be used with an integer variable

Arithmetic Expression

14

Binary OperatorExample:

int A, B;

float C;

A= 2;

B=5;

C= 2.4;

B% A;

C % A;

Valid! Answer is 1

Invalid! C is float

Arithmetic Expression

15

Assignment StatementUsed to store value/result of process to a variable

Use operator symbol =

Assignment statement

Double assignment

statement

Compound assignment

statement

Arithmetic Expression

16

Assignment Statement Format /sintax :

variable = value;

variable = constant; or variable = variable;

variable = expression;

Example :

1.average= ( 6 + 5) * 4;

2.grossSalary = 1500;

nettSalary = grossSalary + 200;

3.price= 50.00;

pay = price;

`

44average

grossSalary1500

nettSalary 1700

price

pay

50.00

50.00

Arithmetic Expression

17

Compound Assignment Statement

Use more than one operator (=)

Example :

int a = b= c = d = e = 250;

int b =2, number =0, total = 0,average =3;

number = b++ = 10;

int age = workHour = 0;

Arithmetic Expression

18 Compound Assignment Statement

To combine two different operator together.

To simplify arithmetic operator

Original function of operator does not affected

Allowed combination are as follow:

Arithmetic Expression

+= , -= , *= , /= , %=

Function

operator:

19 Compound Assignment StatementExample :

Operator Expression Meaning

+= total + = 300 total = total+ 300

-= total - = count+ 300 total = total - (count + 300)

*= total *=300 total = total * 300

/= total /= count– 10 total = total / ( count –10)

%= total % = 7 total = total % 7

Arithmetic Expression

20

Arithmetic Operator Precedence Rules

Compiler will follows the following precedence to execute the arithmetic expression

based on priority.

Operator Arrangement/Priority( ) Left to right

++, -- Right to left

*, /, % Left to right

+, - Left to right

Arithmetic Expression

21

Example:

1. 5 + 2 * 6 – 4 / 2

5 + 12 - 4 / 2

5 + 12 - 2

17 - 2

15

2. 3 * 4 / 2 + ( 3 –1)

3 * 4 / 2 + 2

12 / 2 + 2

6 + 2

8

Arithmetic Operator

Arithmetic Operator Precedence Rules

22

Example:

3. Prefix unary arithmetic expression

int kira = 5, nilai_pertama = 10;

nilai_kedua = 5 * --kira + nilai_pertama;

printf(“%d %d”, kira, nilai_kedua);

Output:

4 30

Arithmetic ExpressionArithmetic Operator Precedence Rules

23

Example:

3. Prefix unary arithmetic expression

int kira = 5, nilai pertama = 10;

nilai_kedua = 5 * kira-- + nilai_pertama;

printf(“%d %d”, kira, nilai_kedua);

Output:

4 35

Arithmetic Expression

Arithmetic Operator Precedence Rules

24 Mathematic Library Function

•Header file designed for basic mathematical operations (math.h)

•Syntax #include <math.h>

•Below are lists of some common math functions :

Fungsi Tujuan

sqrt(x) compute the non-negative square root of x

pow(x,y) computes x raised to the power y

cos(x) compute the cosine of x (measured in radians)

sin(x) computes the sine of x (measured in radians)

tan(x) compute the tangent of x (measured in radians)

Arithmetic Expression

25

Mathematic Library FunctionExample:

#include<stdio.h>

#include <math.h>

void main()

{

int x = 16, y ;

y = sqrt(x);

printf(“%d”,y);

}

Output :

4

Arithmetic Expression

26 Exercise:

1. Convert the following mathematic expression to a valid arithmetic

expression :

a) b = 3 + b b) x = (a – b)(a – c2)

a + 4

c) d = (3e – d) - ( 4 – 3c3 ) d) r = 2s + 3(s – 9)

x – 9 4y s

2. Given a= 3, b = 5, c=1. What is the output of the following expression?

a. ( 6 * c – 6 / a) - b b. (5 * c) +( a* b / b)

c. ++a d. c + a * c / (3 * c)

Arithmetic Expression

27 Exercise:

Assume i,j and k are integer variables with i = 5 and j=3. Determine the value for

each of the following statement:

a) k = j++; d) k = ++j;

b) k = i * j--; e) k = i * --j;

c) k = j + i * j++; f) k = 27 / j++ - 16 % i;

Arithmetic Expression

28

Relationalexpression

useRelational operator

Combination of more than one statement

variable vs variable

variable vs constant

constant vs constant

Can consists of

produce

0 (if false) 1(if true)

Relational Expression

29

Relational OperatorOperator Description

= = Equal to

> Greater than

< Less than

>= Greater than or equal

<= Less than or equal

!= Not equal

Relational Expression

30

int a=6, b =1, c = -2;

1) a+ b == c 2) a != b

6 + 1== -2 6 != 1

7 == -2

Answer: 0(False) Answer : 1 (True)

P/s:

a, b and c are variables,

Replace with the given values

Relational Expression

Example 1:

31

int a=6, b =1, c = -2;

3) b < c 4) b + c <= a

1 < -2 1 + -2 <= 6

-1 <= 6

Answer: 0 (False) Answer : 1 (True)

Relational Expression

Example 2 :

32

int a=10, b = 3, c = 7;

(a+b >= 3*c)==( a != 2*c+b)

(10+3 >= 3*7)==(a != 2*c+b)

(13 >= 21)==(10 != 14+3)

(13 >= 21)==(10 != 17)

0 == 1

0 (false)

P/s:

Relational operator has less priority than

other operators.

Start evaluating from left to right.

Relational Expression

Example 3:

33An example program which uses relational expression

#include <stdio.h>

void main()

{ int age;

printf(“\nPlease enter your age >>”);

scanf(“%d”,&age);

if (age > 21)

printf(“\nYou are qualified to vote”);

}

Relational expression

Relational Expression

34

Logical expression

use

Logical Operator

Combination of one or more expressions

Relational expr. vs logical expr.

Relational expr. vs variable

Relational expr. vs constant

Can consists of

hasilkan

0 (if false) 1(if true)

Logical Expression

35Logical Operator

Operator Description

&& AND

|| OR

! NOT

Logical operator && dan || is used between 2 or more

relational expression

Logical Expression

36

Logical operator truth table for AND

Value 0 1

0 0 0

1 0 1

AND (&&)Logical Operator Result

False AND False False

False AND True False

True AND False False

True AND True True

Logical Expression

37

Logical operator truth table for OR

Value 0 1

1 0 1

1 1 1

OR (||)Logical Operator Result

False OR False False

False OR True True

True OR False True

True OR True True

Logical Expression

38

Value Result

!0 1

!1 0

NOT(!)

Logical Operator Result

Not false True

Not true False

Logical Expression

Logical operator truth table for NOT

39

Example 1:

Evaluate the following logical expression:

a) (2 < 5 ) && ( 5 < 10) b) (7 % 2 < 2) || ( 2 * 3 == 6)

1 && 1 (1 < 2) || (6 == 6)

1 1 || 1

1

Logical Expression

40Example 2:

Evaluate the following logical expression:

Given a = 3, b = 4;

c) !((5 * b <= 23 - a )) d) ! ((b +3 != 8) &&( 3 * a < 2))

!((5 * 4 <= 23 – 3)) !(( 7 != 8 ) && ( 9 < 2 ))

!(20 <= 20) ! ( 1 && 0 )

!(1) ! ( 0)

0 1

Logical Expression

41An example program which using Logical Expression:

#include <stdio.h>

void main()

{ int mark;

printf(“\nEnter your mark >>”);

scanf(“%d”,&mark);

if (mark >= 85 && mark <= 100)

printf(“\nGred A”);

else if( mark >=80 && mark <=84)

printf(“\nGred A-”);

}

Logical Expression

42 Exercise:1. Given with i=2, j = 5 and k = 15. Evaluate each of the following

expression:

a) i > j – k g) k == j + i * j

b) i != k h) k <=k /j

c) (i >= 1) && (j == 5) i) (j < i) || (k > j)

d) !( i > j) j) (i >0) && (j <k) || (k <i)

e) i < j < k k) i * k < k / j

f) (i < j) && (j < k) l) i – j > k

2. Complete the following statements with suitable logical expression.

int angka1,angka2;

if (angka1 is less than or equal to angka2)

printf(“%d is less than or equal to

%d”,angka1,angka2);

Logical Expression

Next Chapter : 4

CONTROL STRUCTURE

4.1 The use of control structure including if,

for and switch

4.2 The use of while loop, break and goto