MELJUN CORTES--IT102 C++ Fundamental BASICS

8/8/2019 MELJUN CORTES--IT102 C++ Fundamental BASICS

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C H A P T E R 2P R O B L E M S O L V I N G U S I N G C + +

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C++ Programming

MELJUN CORTES,BSCS,ACSMELJUN CORTES,BSCS,ACS


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Objectives

y Introduction to C++ : Identifier, keyword, mnemonic

y Programming Style

y Data Types

y Arithmetic Operations

y Variables and Declaration Statements

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Introduction to C++


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y Modular Program: a program consisting ofinterrelated segments arranged in a logical andunderstandable form Easier to develop, correct, and modify than other kinds of

programs

y Module: a small segment which is designed toperform a specific task A group of modules is used to construct a modular program


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Introduction to C++:Identifier


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y Identifier: a name given to an element of thelanguage, such as a class or function

y Rules for forming identifier names:

First character must be a letter or underscore Only letters, digits, or underscores may follow the initial letter

(no blanks allowed)

Keywords cannotbe used as identifiers

Max length of an identifier = 1024 characters

y Use underscores to separate multiple words in aname, or capitalize the first letter of each word.


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Introduction to C++:Keyword


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y Keyword: a reserved name that represents a built-inobject or function of the language


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Introduction to C++:Identifier (continued)


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y Identify valid C++ identifiers below: degToRad

1AB3

addNumswhile

slope

findMax

E*6

valid

valid

valid

valid

invalid begins with a number

invalid contains a specialcharacter

invalid this is a keyword


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Introduction to C++:Mnemonic


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y Function names Require a set of parentheses at the end

Can use mixed upper and lower case

Should be meaningful, or be a mnemonic

y Mnemonic: a word designed as a memory aid

Examples of function names:

areaCircle() calAverage() main()

y

Note that C++ is a case-sensitive language!


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Introduction to C++:Themain() Function


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y Overall structure of a C++ program contains onefunction namedmain(), called the driver

function

y All other functions are invoked frommain()y Each statement inside the function mustbe

terminated with a semicolon

y return: a keyword causing the appropriate value to

be returned from the function

y return 0 in themain() function causes the

program to end


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Introduction to C++:Themain() Function (continued)


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y The structure of amain() function.


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Introduction to C++:The cout Object

USEG20/Saidatul Rahah

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y cout object: an output object that sends data to a

standard output display device


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Objectives


y Programming Style

y Data Types



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Programming Style


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Although more than one C++ statement can be ona single line, good style calls for one statement perline

Opening and closing braces {} for the functionbody should each be on separate lines

Statements in the function body should beindented


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Programming Style: Comments


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y Comments: explanatory remarks in the source code addedby the programmer

y Line comment:begins with // and continues to the end ofthe line Line comment can be on a line by itself, or at the end of a line

of code Line comment cannot be longer than one line

y Block Comment: a comment that spans across two or morelines Block comment begins with /* and ends with */

Example:/* This is a block comment that

spans

across three lines */


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Programming Style: Comments(continued)


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Objectives


y Programming Style

y Data Types



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Data Types


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Data type: a set of values and the operations thatcan be applied to these values

Two fundamental C++ data groupings:

Class data type (a class): created by theprogrammer

Built-in data type (primitive type): part of theC++ compiler


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Data Types (continued)


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Numerical Data

Types

y Built-in data types

Integer Types Floating-PointTypes


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Data Types: Integer


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Data Types: Integer (continued)


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y int data type: whole numbers, optionally with + or signExample: 2

y

char data type: individual character; any letter,digit, or special character enclosed in single quotesExample: A

y Character values are usually stored inASCII code


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y Escape character: the backslash, \; indicates anescape sequence

y Escape sequence: tells compiler to treat the

following characters as special instruction codes


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Refer Table2.4: EscapeCharacter.

p61


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ybool data type: represents Boolean (logical) data;restricted to two values: true or false

y sizeof operator: shows the number of bytes used to

store values of any data typey Values returned bysizeof are compiler dependent


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y Signed data type: one that permits negative,positive, and zero values

y Unsigned data type: permits only positive and

zero valuesy An unsigned data type provides essentially double

the range of its signed counterpart


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Data Types: Floating-Point Types


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y Floating-point number (real number): zero orany positive or negative number containing adecimal point

Examples: +10.625 5. -6.2

y No special characters are allowed

y Three floating-point data types in C++: float (single precision)

double (double precision)

long double


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Data Types: Floating-Point Types(continued)


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Objectives


y Programming Style

y Data Types

yArithmetic Operations


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Arithmetic Operations


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Arithmetic operators are binary operators

Binary operators: require two operands

Different data types can be used in the same arithmetic

expressionOperation Operator

Addition +

Subtraction -

Multiplication *Division /

Modulus(remainder)

%


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Arithmetic Operations:Expression Types


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y Expression: any combination of operators and operandsthat can be evaluated to yield a value

y Mixed-mode expression: contains integer and floating-point operands; yields a double-precision value

15 + 5 = 20

operatoroperands


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Arithmetic Operations :Summary of Operators


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Arithmetic Operations (continued)


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IntegerData Type

7 + 3 = 10

7 3 = 4

7 * 3 = 21

7 / 3 = 2

7 % 3 = 1

Floating Point DataType

7.0 + 3.0 = 10.0

7 .0 3.0 = 4.0

7.0 * 3.0 = 21.0

7.0 / 3.0 = 2.33

If both operands are integer data type,output will be INTEGERIf ONE operand is floating point dataType, output will be FLOATING POINT


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Arithmetic Operations:Operator Precedence & Associativity


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y Rules for writing arithmetic expressions: Never place two consecutive binary arithmetic operators side

by side

Use parentheses to form groupings; contents within

parentheses are evaluated first You may nest parentheses within other parentheses; evaluated

from innermost to outermost

Use the * operator for multiplication, not parentheses


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Arithmetic Operations:Operator Precedence & Associativity (continued)


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y Expressions with multiple operators are evaluated byprecedence of operators

y Associativity: the order in which operators of the sameprecedence are evaluated


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Arithmetic Operations:Operator Precedence & Associativity (continued)


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y Example:

8 + 5 * 7 % 2 * 4

= 8 + 35 % 2 * 4

= 8 + 1 * 4

= 8 + 5

=12


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Objectives


y Programming Style

y Data Types


yVariables and Declaration Statements

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Variables and Declaration Statements


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Variable: symbolic identifier for a memory address wheredata can be held

Use identifier naming rules for variable names


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Variables and Declaration Statements(continued)


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yAssignment statement: used to store a value intoa variable

y Value of the expression on the right side of the = is

assigned to the memory location of the variable onthe left side of the =

Examples:

num1 = 45;

num2 = 12;total = num1 + num2;

45

num1


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Variables and Declaration Statements(continued)


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y Declaration statement: specifies the data typeand identifier of a variable; sets up the memorylocationSyntax: ;

y A variable must be declaredbefore it is used!

y Data type is any valid C++ data typeExample:

int sum;

int num1, num2, num3;

float pi = 3.142;

Initialized indeclaration


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Problem Solving


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y Write a C++ program to calculate the average of twodouble-precision numbers.Apply Software Development Procedure:

Step 1: Analyze the problem

Output - average

Inputs - 2 numbers ( num1, num2)

Step 2: Develop a solutionAssign values to num1 and num2

Calculate and displayaverageStep 3: Code the solution

Step 4: Test and correct the program


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Problem Solving (continued)


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y Flowchart:start

Input 2numbers

Calculateaverage

Displayaverage

end

#include

int main(){

double num1, num2, average;

num1 = 45.5;num2 = 10.2;average = (num1+num2)/2;

cout


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Common Programming Errors


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y Missing parentheses aftermain

y Missing or incorrect braces around function body

y Misspelling a reserved word

y Missing ending double quotes on string literal

y Missing semicolon at end of statement

y Adding a semicolon at end of#include statement

y

Missing \n to indicate new liney Substituting letter O for zero and vice versa


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Common Programming Errors (continued)


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y Failing to declare all variables

y Storing incorrect data type into a variable

y Attempting to use a variable with no value

y Dividing integer values incorrectly

y Mixing data types in the same expression


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Short Quiz


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y Write down your name, SID no, class name on apiece of paper and answer below question.

1. List 4 rules for forming identifier names.

2. Solve expression given below.

12 + 5 % 2 * 8 3

Thank You for Listening..

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MELJUN CORTES--IT102 C++ Fundamental BASICS

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