CHAPTER 2 PROBLEM SOLVING USING C++ 1 C++ Programming PEG200/Saidatul Rahah.

CHAPTER 2PROBLEM SOLVING USING C++

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C++ Programming

PEG200/Saidatul Rahah

Objectives

Introduction to C++ : Identifier, keyword, mnemonic

Programming StyleData TypesArithmetic OperationsVariables and Declaration Statements

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USEG20/Saidatul Rahah

Introduction to C++


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Modular Program: a program consisting of interrelated segments arranged in a logical and understandable form Easier to develop, correct, and modify than other

kinds of programsModule: a small segment which is designed

to perform a specific task A group of modules is used to construct a modular

program

Introduction to C++(continued)


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Modules in C++ can be classes or functions: Function: accepts an input and produces an output

by processing the input in some fashion A function’s processing is encapsulated and hidden

within the function Class: contains both data and functions used to

manipulate the data Function: encapsulates a set of operations, while a class

encapsulates data plus one or more sets of operations

Introduction to C++:Identifier


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Identifier: a name given to an element of the language, such as a class or function

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 cannot be used as identifiers Max length of an identifier = 1024 characters

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

Introduction to C++:Keyword


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Keyword: a reserved name that represents a built-in object or function of the language

Introduction to C++:Identifier (continued)


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Identify valid C++ identifiers below: degToRad 1AB3 addNums while slope findMax E*6

valid

valid

valid

valid

invalid begins with a number

invalid contains a special character

invalid this is a keyword

Introduction to C++:Mnemonic


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Function names Require a set of parentheses at the end Can use mixed upper and lower case Should be meaningful, or be a mnemonic

Mnemonic: a word designed as a memory aidExamples of function names:areaCircle() calAverage() main()

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

Introduction to C++: The main() Function


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Overall structure of a C++ program contains one function named main(), called the driver function

All other functions are invoked from main()Each statement inside the function must be

terminated with a semicolonreturn: a keyword causing the appropriate

value to be returned from the functionreturn 0 in the main() function causes the

program to end

Introduction to C++: The main() Function (continued)


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The structure of a main() function.

Introduction to C++: The cout Object


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cout object: an output object that sends data to a standard output display device

Objectives



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Programming Style


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• Although more than one C++ statement can be on a single line, good style calls for one statement per line

• Opening and closing braces {} for the function body should each be on separate lines

• Statements in the function body should be indented

Programming Style: Comments


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Comments: explanatory remarks in the source code added by the programmer

Line comment: begins with // and continues to the end of the 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

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

Example:/* This is a block comment that

spans across three lines */

Programming Style: Comments(continued)


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Objectives



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Data Types


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• Data type: a set of values and the operations that can be applied to these values

• Two fundamental C++ data groupings:– Class data type (a class): created by the

programmer– Built-in data type (primitive type): part

of the C++ compiler

Data Types (continued)


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Numerical Data Types

Built-in data types

Integer Types Floating-PointTypes

Data Types: Integer


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Data Types: Integer (continued)


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int data type: whole numbers, optionally with + or – sign Example: 2

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

Character values are usually stored in ASCII code



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Escape character: the backslash, \; indicates an escape sequence

Escape sequence: tells compiler to treat the following characters as special instruction codes


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Refer Table 2.4: Escape Character. p54



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

sizeof operator: shows the number of bytes used to store values of any data type

Values returned by sizeof are compiler dependent



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

Unsigned data type: permits only positive and zero values

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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Floating-point number (real number): zero or any positive or negative number containing a decimal pointExamples: +10.625 5. -6.2

No special characters are allowedThree floating-point data types in C++:

float (single precision) double (double precision) long double

Data Types: Floating-Point Types (continued)


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Objectives



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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 expression

Arithmetic Operations: Expression Types


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Expression: any combination of operators and operands that can be evaluated to yield a value

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

15 + 5 = 20

operatoroperands

Arithmetic Operations :Summary of Operators


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Arithmetic Operations (continued)


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Integer Data Type

7 + 3 = 10

7 – 3 = 4

7 * 3 = 21

7 / 3 = 2

7 % 3 = 1

Floating Point Data Type

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 INTEGER•If ONE operand is floating point data Type, output will be FLOATING POINT

Arithmetic Operations: Operator Precedence & Associativity


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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


(continued)


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Expressions with multiple operators are evaluated by precedence of operators

Associativity: the order in which operators of the same precedence are evaluated


(continued)


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Example:8 + 5 * 7 % 2 * 4= 8 + 35 % 2 * 4= 8 + 1 * 4= 8 + 5=12

Objectives



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Variables and Declaration Statements


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• Variable: symbolic identifier for a memory address where data can be held

• Use identifier naming rules for variable names

Variables and Declaration Statements (continued)


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Assignment statement: used to store a value into a variable

Value of the expression on the right side of the = is assigned to the memory location of the variable on the left side of the =Examples:

num1 = 45;num2 = 12;total = num1 + num2;

45num1

Variables and Declaration Statements (continued)


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Declaration statement: specifies the data type and identifier of a variable; sets up the memory locationSyntax: <dataType> <variableName>;

A variable must be declared before it is used!

Data type is any valid C++ data typeExample:

int sum;int num1, num2, num3;float pi = 3.142; Initialized in

declaration

Problem Solving


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

Step 1: Analyze the problemOutput - average Inputs - 2 numbers ( num1, num2)

Step 2: Develop a solution Assign values to num1 and num2 Calculate and display average

Step 3: Code the solution Step 4: Test and correct the program

Problem Solving (continued)


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Flowchart:start

Input 2 numbers

Calculate average

Display average

end

#include <iostream.h>

int main(){ double num1, num2, average; num1 = 45.5; num2 = 10.2; average = (num1+num2)/2;

cout<<“Average is: “<<average;

return 0;}

Variable declaratio

n

Assignment statement

output

Common Programming Errors


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Missing parentheses after mainMissing or incorrect braces around function bodyMisspelling a reserved wordMissing ending double quotes on string literalMissing semicolon at end of statementAdding a semicolon at end of #include statementMissing \n to indicate new lineSubstituting letter O for zero and vice versa

Common Programming Errors (continued)


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Failing to declare all variablesStoring incorrect data type into a variableAttempting to use a variable with no valueDividing integer values incorrectlyMixing data types in the same expression

Short Quiz


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Write down your name, SID no, class name on a piece 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…..

CHAPTER 2 PROBLEM SOLVING USING C++ 1 C++ Programming PEG200/Saidatul Rahah.

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