Chapter 2 Wk3

CHAPTER 2CHAPTER 2COMPONENTS OF A COMPONENTS OF A

PROGRAMMING PROGRAMMING LANGUAGELANGUAGE

INTRODUCTION TO INTRODUCTION TO COMPUTER COMPUTER

PROGRAMMINGPROGRAMMING(CSC425)(CSC425)

CONTENTS

Arithmetic Expressions Operators

Addition, subtraction,multiplication, division, modulus

Binary and unary operator Negation operator

2CSC425 : INTRODUCTION TO COMPUTER PROGRAMMING

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Variables and constants of integral and floating point

types can be combined into expressions using

arithmetic operators.

In C++, we have to represent the algebraic

expression by using the valid syntax.

ARITHMETIC EXPRESSION

CSC425 : INTRODUCTION TO COMPUTER PROGRAMMING

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Is the most basic C++ statement Use to store the value of an expression in a variable Use Assignment Operator (=) Syntax:variable = <variable|constant|expression>

Expression can be :i. a constantii. another variableiii. an arithmetic expressioniv. a function

Assignment statement


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Examples:

length = oldLength;width = 50;area = length * width;moredata = true; //a boolean variablex = total ( );

Assignment statement


ARITHMETIC OPERATOR

Generally, there are three types of operator: Unary Binary Ternary

These term reflect the number of operands an operator requires.

Unary operators only require a single operand. Ex: -7 Represent the value negative 7 The literal 7 is preceded by the minus sign, is

called the negation operator. Since it only requires one operand, it is a unary

operator

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ARITHMETIC OPERATOR CONT…

Binary operator work with two operands Ex: total = cost + tax;

Average = total / 3; Ternary operator work with three operands

Ex: total = num1 + num2 + num3;

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Assignment Operation

Variations of Assignment Operation : We can have assignment statement like this :

sum = sum + 10; This statement can be written using the following

shortcut assignment operators :

+= -= /= %= *=

Hence, the equivalent “sum = sum + 10”, would be :

sum += 10;


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ARITHMETIC EXPRESSION Example :

Expression Equivalent to

price = price * rate; price *= rate;

count = count + 3 count += 3

price *= rate + 1 price = price * (rate + 1)

but not

price = price * rate + 1


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Assignment Operation For a variable to increase or decrease by 1, C++ provides two

unary operators :

(++) : increment operator

(--) : decrement operatoro Increment & Decrement Operators:

Expression Equivalent to

i = i + 1 i++ (postfix increment operator)

If x = 5; and y = x++;

After the second statement y is 5 and x is 6

i = i - 1 i--


Arithmetic Operators Defined in C++ Example

Addition + 20.9 + 3 = 23.9, or 20 + 3=23

Subtraction - 50 – 10 =40, or 50.4-10= 40.4

Multiplication * 10*3=30, or 10.5*3= 31.5

Division / 10/3 = 3 , or 10.0/3= 0.3333

Modulus

(remainder)

% 10%3=1

Never use the modulus with floating-

point values.

Operators

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Mathematical Library Functions

Header file #include <math.h> used in the following form :

function_name(argument)

Example :sqrt(x) //square root of xpow(a,2) //a2

fabs(2.3 * 4.6) //absolute value |x|tan(x) //tangent of xfloor(x) //largest integer <= x

More reference at:http://www.cplusplus.com/reference/cmath/floor/


Arithmetic Operations Examples

#include<iostream.h>

void main (){

int number1, number2;

int sum, different, product, quotient, remainder ;

number1 = 8;

number2 = 4;

sum = number1 + number2;

different = number1 - number2;

product = number1 * number2;

quotient = number1 / number2;

remainder = number1 % number2;

cout<<"sum : " <<sum<<endl;

cout<<"different: " <<different<<endl;

cout<<"product : " <<product<<endl;

cout<<"quotient : " <<quotient<<endl;

cout<<"remainder : " <<remainder<<endl;

}

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Output:

Integer Division

IF two integers are divided, the result will be an integer number. Any fraction will be truncated.

int / int int

Example:

int a = 5, b = 2;float c;c = a / b; //the new value of c is 2

cout << a / b; //2 will be displayed

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Arithmetic Operations


When more than one operator will be executed to determine the result, C++ executes the arithmetic operators in the following order:

Operator (s) Operation Precedence

( ) parentheses Evaluated first, inside-out if nested or left to right if same level

*,/,% Multiply, Divide, Modulus

Evaluated second, left to right

+, - Add, Subtract Evaluated last, left-to-right

Precedence & Associativity

Example:a) 3 * 7 – 6 + 2 * 5 / 4 + 6

means( 3 * 7 ) – 6 + ( ( 2 * 5 ) / 4 ) + 6

= 21 – 6 + ( 10 / 4 ) + 6 ( evaluate * )= 21 – 6 + 2 + 6 ( evaluate / )= 21 – 6 + 8 ( evaluate + )= 21 + 2 ( evaluate +)= 23 ( evaluate +=

result)


b) 3 + 4 * 5 means

3 + ( 4 * 5 )= 3 + 20 ( evaluate * )= 23 ( evaluate + )

c) 2 * 3 / 2 (evaluate operators from

left to right)= 6 / 2

(evaluate * )= 3 (evaluate / )


Write a program that does the following :

1. Find the sum, subtract and average of two integers

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Exercise 1


Try to write a program : Convert Length

Write a program that takes as input given lengths expressed in meters and millimeters. The program should then convert and output the length in centimeters. Assume that the given lengths in meters and milimeters are integers.

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Exercise 2


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Translate the following flow chart into source code:

Begin

End

Read total

Read count

Display average

average = total / count

Exercise 3


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Given the following declaration:

int a, b, c, v1, v2;

a = 8;

c = b = 3;

c = c – 1;

v1 = a / b;

v2 = a / c;

What is the final content of a, b, c, v1 and v2?

Exercise 4


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Chapter 2 Wk3