Introduction to Programming

Introduction to Programming

Course Introduction

• Programming Languages• CSE-112• Credit hours: 2-1

– 2 classes / week– 1 lab / week


Course Contents


Topics

Introduction to Programming, IDE, Console output, Good programming practices

Algorithms, Pseudo codes, Flow Charts

Implicit and Explicit Type conversions, Logical and Mathematical operators

Conditions

Loops

Single and Multidimensional Arrays

Functions, Scope, Lifetime, Recursive functions

Course Contents


Topics

Strings

Pointers

Structures, Unions and Enumerations

Indexing, file input output

Dynamic Memory Allocation (DMA), Application of DMA in a linked list

Classes and Objects

Inheritance, Polymorphism, Encapsulation

Data Structures : Stacks, queues, trees

Grading Policy


Distribution Percentages

Assignments 0%

Quizzes 15%

OHT 30%

Project 15%

Final 40%

Books

COURSE TEXT BOOK• Object oriented programming in C++(4th edition) Robert Lafore • C++ How to program(4th edition) Deitel & Deitel

REFERENCE BOOK• Let us C++ - Yashavant Kanetkar• Aikman Series-Programming in C++ object oriented programming - C

M Aslam• C++ An Introduction to Programming – Jesse Liberty, Jim Keogh• Programming and Problem Solving with C++ (4th Edition) - Nell Dalle


Introduction


Computer Software

• Application Software– Word processors, spread sheets, presentation managers

• System Software– Programs that support the execution and development of

other programs• Operating systems

• Translation systems


Translation System

• Set of programs used to develop software• Translators

– Compiler– Linker

• Examples– Microsoft Visual C++– JBuilder


Computer Languages

• Three types of computer languages– Machine Level language

• Only language computer directly understands• Consists of strings of numbers (0’s and 1’s)

– Assembly language• Abbreviations representing elementary computer operations • Requires many instructions to accomplish simple tasks• LOAD, ADD, STORE

– High level language• Single statements accomplish substantial tasks• C++ , Java


Program Writing


Compile

Link

Library routines

Other object files

Think

Edit

Load

Execute

Source Program

IDEs• Integrated Development Environments or IDEs

– Supports the entire software development cycle• MS Visual C++, Borland

• Provides all the capabilities for developing software– Editor– Compiler– Linker– Loader– Debugger– Viewer


A Sample Program


// first program in C++

#include <iostream.h>

void main (void)

{

cout << "Hello …";

}

Executing the Program


Source file “Test.cpp”

Test.cpp Compile

Test.obj

Test.obj + LibrariesLink

Test.exe



void main (void)

{


}

A Sample Program




void main (void)

{


}

A comment

Header File : contains function declarations

Start function

Program Statements

Program Output

• Output Terminal?– Console– Data File– Terminal ports/ sockets

• Console Output– cout <<– In the header file “iostream”


Escape Sequences

Escape Sequence Description

\n Newline. Position the screen cursor to the beginning of the next line.

\t Horizontal tab. Move the screen cursor to the next tab stop. \r Carriage return. Position the screen cursor to the beginning

of the current line; do not advance to the next line. \a Alert. Sound the system bell. \\ Backslash. Used to print a backslash character. \" Double quote. Used to print a double quote character.

Console Output

• How to generate the following output:

******************Name

My nameRoll No

My roll no ******************


Good Programming Practices

• First design the basic flow chart of the program• Write the pseudo code

– Simple English statements• Algorithm

– English and Programming terms• Code the algorithm

– Use already given libraries, don’t re-invent the wheel• Check for errors

– Different types of errors• Example : Even /odd numbers


Program Errors

Compiler Errors

Error Test.cpp 4: Statement Missing ; in function main()Error Test.cpp 4: Compound Statement missing } in function main()


void main (void)

{

cout << "Hello …"

Program Errors

Linker Error: Undefined Symbol _main

Linker Errors


void Main (void)

{


}

Program Errors

These errors don’t reveal themselves until the program executes.

Run-Time Errors


void main (void)

{

int a=0;

int b=10;

double c = b/a;

}

Program Errors

The program is not doing what you expect it to do.

Conceptual Errors#include <iostream.h>

void main (void)

{

int a=4;

int b=10;

int c = b/a;

cout << “c = “<< c;

}

Programming Basics

C++ Data Types

Integer Data types

char short int long

Floating Point Data types float double long double

Programming Basics

C++ Data Types

Data Type No. of Bytes No. of Bits

char 1 8

short 2 16

int 4 32

long 4 32

float 4 32

double 8 64

long double 10 80

Programming Basics

C++ Data Types

• Integer Data Types– Range– Unsigned Data Types

Type Sign Size Min Value Max Value

short signed

unsigned

16 bits -32768

0

32767

65535

int Signed

unsigned

32 bits -2,147,483,6480

2,147,483,6474,294,967,295

long signed

unsigned

32 bits -2,147,483,6480

2,147,483,6474,294,967,295

Programming Basics

Declarations

• Declarations– Constant Declarations– Variable Declarations

• Constant Declarations Constants are used to store values that never change

during the program execution.

Using constants makes programs more readable and maintainable.

Programming Basics

Declarations

• Constant Declarations– Syntax

const <type> <identifier> = <expression>;

Example

const double PI = 3.1459;

Programming Basics

Declarations

• Variable Declarations– Variables are used to store values that can be changed

during the program execution

Syntax::

< type > < identifier >;< type > < identifier > = < expression >;

Examples:

int sum;int total = 3445;char answer = 'y';double temperature = -3.14

Programming Basics

Declarations

• A variable has a type and it can contain only values of that type. For example, a variable of the type int can only hold integer values

• Variables are not automatically initialized. For example, after declaration

int sum;

the value of the variable sum can be anything (garbage).

• Thus, it is good practice to initialize variables when they are declared. Once a value has been placed in a variable it stays there until the program deliberately alters it.

Programming Basics

Declarations

• Constants and variables must be declared before they can be used

• When you declare a constant or a variable, the compiler:

Reserves a memory location in which to store the value of the constant or variable.

Associates the name of the constant or variable with the memory location.

integer1 45int integer1 = 45;

Programming Basics

Identifiers

• Series of Characters (letters, digits, underscores)• Must NOT start with a digit (0 – 9)• Must not be a C++ keyword• Case Sensitive

Programming Basics

Lvalues & Rvalues

• Lvalues– Expressions that can appear on left side of equation– Can be changed (I.e., variables)

• x = 4;

• Rvalues– Only appear on right side of equation– Constants, such as numbers (i.e. cannot write 4 = x;)

• Lvalues can be used as Rvalues, but not vice versa

Programming Basics

Example12 // Addition program.3 #include <iostream.h>4 5 // function main begins program execution6 void main()7 {8 int integer1; // first number to be input by user 9 int integer2; // second number to be input by user 10 int sum; // variable in which sum will be stored11 12 cout << "Enter first integer:\n"; // prompt13 cin >> integer1; // read an integer14 15 cout << "Enter second integer:\n"; // prompt16 cin >> integer2; // read an integer17 18 sum = integer1 + integer2; // assign result to sum19 20 cout << "Sum is " << sum << endl; // print sum21 2223 24 } // end function main

Programming Basics

Input Value

• Input Source?– Console– Data File

• Console Input– cin >>– In the header file “iostream”

Programming Basics

Arithmetic Operators

• Arithmetic calculations– *

• Multiplication

– / • Division• Integer division truncates remainder

7 / 5 evaluates to 1

– %• Modulus operator returns remainder

7 % 5 evaluates to 2

– + and –• Addition and Subtraction

Programming Basics


Operator(s) Operation(s) Order of evaluation (precedence)

() Parentheses Evaluated first. If the parentheses are nested, the expression in the innermost pair is evaluated first. If there are several pairs of parentheses “on the same level” (i.e., not nested), they are evaluated left to right.

*, /, or % Multiplication Division Modulus

Evaluated second. If there are several, they re evaluated left to right.

+ or - Addition Subtraction

Evaluated last. If there are several, they are evaluated left to right.

• Rules of operator precedence

Programming Basics


• Priority of operators– a = 5 + 7 % 2;– we may doubt if it really means:

• a = 5 + (7 % 2) with result 6 or• a = (5 + 7) % 2 with result 0

– Parentheses are included when one is not sure

• sizeof ( )– returns the size in bytes– a = sizeof (char)

Programming Basics


• Arithmetic Assignment Operators a = a + b; a+=b;

void main(void){

int number = 15;number +=10;cout << number << endl;number -=7;cout << number << endl;number *=2;cout << number << endl;number %=2;cout << number << endl;

}

Programming Basics

25

18

36

0


• Increment Operators count = count + 1; count +=1; count++; OR ++count;

int a = 5;int b = 10;int c = a * b++;

int a = 5;int b = 10;int c = a * ++b;

Programming Basics

50 55


• Decrement Operators count = count - 1; count -=1; count--; OR --count;

postfix prefix

Programming Basics


void main(){

int count = 10;

cout << count << endl;cout << ++count << endl;cout << count << endl;cout << count++ << endl;cout << count << endl;

}

1011111112

Programming Basics

Type Conversion

• Automatic Type Conversion• Casting

Automatic Type Conversion:

void main (void){

int number = 2;float factor = 1.5;double result = number * factor;cout << “Result is: “ << result;

}

Programming Basics

Type Conversion

void main(void){

short number = 30000; //-32768 to 32767short result = (number * 10) / 10;cout << “Result is: “ << result; //Result Incorrect

}

number = 30000;result = ( long(number) * 10 ) / 10; //Castingcout << “Result is: “ << result;

• Casting

Programming Basics

Relational Operators

• To evaluate comparison between two expressions– Result : True / False

Programming Basics

Standard algebraic equality operator or relational operator

C++ equality or relational operator

Example of C++ condition

Meaning of C++ condition

Relational operators

> > x > y x is greater than y

< < x < y x is less than y

>= x >= y x is greater than or equal to y

<= x <= y x is less than or equal to y

Equality operators

= == x == y x is equal to y

!= x != y x is not equal to y

Relational Operators

• Examples (7 == 5) would return false (3 != 2)would return true (6 >= 6) would return true

• If a=2, b=3 and c=6 (a*b >= c) would return true since it is (2*3 >= 6) (b+4 > a*c) would return false since it is (3+4 > 2*6) ((b=2) == a) would return true

Programming Basics

Equality (==) and Assg (=) Operators

• Common error : Does not cause syntax errors

• Exampleif ( payCode == 4 )

cout << "You get a bonus!“;

• If == was replaced with =if ( payCode = 4 ) cout << "You get a bonus!“;

– PayCode set to 4 (no matter what it was before)– Statement is true (since 4 is non-zero)– Bonus given in every case

Programming Basics

Logical Operators

• NOT, AND, OR : ( !, &&, || )– Operator ! is equivalent to Boolean operation NOT

• ! (5 == 5) returns false• ! (6 <= 4) returns true• ! true returns false.• ! false returns true.

– Logic operators && and || are used when evaluating two expressions to obtain a single result

• ((5 == 5) && (3 > 6)) returns false (true && false) • ((5 == 5) || (3 > 6)) returns true ( true || false ).

Programming Basics

Conditional Operators

• condition ? result1 : result2 if condition is true the expression will return result1, if not

it will return result2

• Examples 7==5 ? 4 : 3 returns 3 since 7 is not equal to 5. 7==5+2 ? 4 : 3 returns 4 since 7 is equal to 5+2 a>b ? a : b returns the greater one, a or b

Programming Basics

Bitwise Operators

• Bitwise Operators ( &, |, ^, ~, <<, >> )

Programming Basics

& AND Logical AND| OR Logical OR^ XOR Logical exclusive OR~ NOT Complement to one (bit inversion)<< SHL Shift Left>> SHR Shift Right

Documents

Introduction to Programming