class10 12c++ fundamentals

8/2/2019 Class10 12C++ Fundamentals

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FUNDAMENTALS OF C++


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Objective

Become familiar with fundamental tokens anddata types

Write simple computer program in C++

Use simple Output statements

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History of C

C is a high level language.o Evolved by Dennis Ritchie and Brain Kernighan(1978)o from two previous programming languages, BCPL

(Basic Combined Programming Language ) and Bo Used to develop UNIX system software routineso Is implemented on UNIX operating systemo Structural / Modular Programmingo Portable & have compilers for almost all architectures.

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C++

C with classes (1979) C++ (1983)o Superset of C developed by Bjarne Stroustrupat Bell Labs and provides object-oriented

capabilities named c with classes.o

Object-oriented design is very powerful 10 to 100 fold increase in productivity

o Dominant language in industry and academia.

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Simple C++ program

// Display This is my first C++ program// Single line comment#include // preprocessor directivevoid main( ) // Entry point for program execution{ // block of statements: Begin

clrscr( ); //Each Statement ends with ;cout


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Simple C++ Programs..// Multi lines comment

/* Find the avg. of three marks anddisplay pass or fail */

#include void main(){cout > marks1>> marks2>> marks3;avg = (marks1+marks2+marks3)/avg;

if (avg < minimum )cout


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Analogy between learning English

Language and C++ Steps in learning English Language:

oAlphabetso Words

o Sentenceo Paragraphs

Steps in learning C++o

Alphabets, Digits, Special Symbolso Constants, Variables, Keywordso Instructionso Programs

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THE C++

CHARACTER SET, IDENTIFIERSKEYWORDS, CONSTANTS

DATA TYPES, VARIABLES

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Consists of letters, digits, special characters, whitespaces.(i) Letters a, b, c,..z OrA, B, C,.Z(ii) Digits 0, 1, 2,9

(iii) Special characters ;, ?, >,


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C++ Tokens

Tokens

Keywords Identifiers Operators Strings constantsSpecial

Symbols

Keywordswords that are basically sequence of charactersdefined by a computer language that have one or more fixedmeanings. They are also called as reserve words. Key wordscannot be changed. Eg. int, float, do-while, if, else,..


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Keywords Each keyword has a predefined purpose in the language. Do not use keywords as variable and constant names!! Some of the C/C++ keywords are

auto, bool, break, case, catch, class, char, const, continue, do,default, delete, double, else, extern, enum, false, float, for, friend,goto, if, int, inline, long, namespace, new, operator, private, protected,public, register, return, short, static, struct, sizeof, switch, template,this, throw, try, typedef, true, unsigned, virtual, void, volatile, while

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Identifiers allow us to name data and other objects in

the program.Each piece of data is stored at unique address instead ofusing addresses, names are usedExample: user defined names likeamount, avg,

Operators +, -, *, %, /, Strings ManipalConstants -15, 10Special Symbols { } (,

C++ Tokens


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Identifiers

An identifier is a name for a variable, constant, function, etc.

It consists ofa letterfollowed by any sequence of letters,digits, and underscores.

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A valid identifier is a sequence of one or more letters,digits or underscore character (_).

Neither spaces nor punctuation marks or symbols can bepart of an identifier

Only letters, digits and underline characters are valid variable identifiers always have to begin with a letter

They can also begin with an underscore character (_ ),but this is usually reserved for compiler specific keywords

or external identifiers.

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Identifiers rules


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They can not begin with a digit.

The C/C++ is a "case sensitive" language.

An identifier written in capital letters is not equivalent toanother one with the same name but written in small

letters.

The RESULT variable is not the same as the resultvariable or the Result variable

They cannot match any keyword of the C++ language oryour compiler's specific ones since they could beconfused with these.

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Identifiers rules


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Examples of valid identifiers: First_name, age, y2000,y2k

Examples of invalid identifiers: 2000y Identifiers cannot have special characters in them. For

example: X=Y, J-20, ~Ricky,*Michael are invalididentifiers.

Identifiers are case-sensitive.For example: Hello, hello, WHOAMI, WhoAmI, whoamiare unique identifiers.

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Identifiers


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A value that IS NOT going to be changed during theexecution of our program;

Constant are specific values that are used in arithmeticexpressions or assigned to variables, e.g. 2, 5, -10, 2.e+6,

3.14159, and so forth; Sometimes a constant represents truly a constant value in

nature such as:

Pi 3.14159

speed of light 2.99792+E8 meters/sec

Constants


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Constants


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Integer ConstantsRefers to a sequence of digits.Decimal, Octal , Hexadecimal.

o Decimal: set of digits 0 to 9, preceded by

optional or + signo Octal: digits 0 to 7 with a leading 0o Hexadecimal: digits 0 to 9, char A to F

preceded by 0xE.g.: 143, -564, 0346, 0x34, 0x8AF

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Numeric Constants


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Used to represent numbers with fractional partE.g.; 213.45, .456,234.

Another form mantissa e exponent0.56e4, 3.12E4 , -4.6E-1

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Floating Point Constant

Character ConstantsSingle characterSingle character with in a pair ofsingle quote ( )

marks, having integer values known as ASCIIvalues.E.g.: d, t, 9


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A sequence of characters enclosed in doublequotes ( ). Characters may be letters, numbers,special characters and blank space.E.g.: hello, 2007, T, 4+5

Backslash character constants

Used in output functionsE.g.: \n new line, \0 null char, \a, \b, \t, \

Also known as escape characters.

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String Constants


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Which helps us to associate an identifier with a constantvalue in your program;

The advantage is that you can refer to the identifier anytime you need to use the constant value instead of having

to repeat writing the value; To declare a symbolic constant you must do it as follows:

constdata typeidentifier= value;

Symbolic Constants


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Consider the Example below:

void main() { float area, perimeter;

float radius; const double Pi = 3.14159;

area = radius * radius * Pi; perimeter = 2 * Pi * radius; cout


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A variable is a data name that may be used to store adata value. A variable may take different values at different times

during execution. Variable name chosen by the programmer in a

meaningful way. Each variable needs an identifier that distinguishes it

from the others.( rules similar to identifier)

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Variables


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C++ data Types


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Data types

C++ Language is rich in its data typesMainly 4 classes of data types Primary (fundamental or Built-in type) data types, User defined Data types Derived Data types

Thefundamental or Built-in data typesfall into one ofthree categories Integer type Floating-point type

Character type Empty data set.


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Primary (built-in or Basic)Data types

void

SIGNED TYPE UNSIGNED TYPEINT UNSIGNED INT

SHORT INT UNSIGNED SHORT INTLONG INT UNSIGNED LONG INT

SIGNED CHARCATERUNSIGNED CHARACTER

FLOATDOUBLE

LONG DOUBLE

INTEGER CHARACTER

FLOATING POINT TYPE

INTEGRAL TYPE


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Integer Types

The basic integer type is into The size of an int depends on the machine and the

On PCs it is normally 16 or 32 bits

Modifierso short: typically uses less bitso long: typically uses more bitso unsignedo signed

Different types allow programmers to use resources moreefficiently.

Standard arithmetic and relational operations areavailable for these types.

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short intint

long int


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SIZE AND RANGE OF VALUES FOR A16-BIT MACHINE (INTEGER TYPE)

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Type Size(bits)

Range

short

short int orsigned short int 8 -128 to 127

unsigned int 8 0 to 255

integerint or signed int 16 -32,768 to 32,767

unsigned int 16 0 to 65,535

long

long int orsigned long int 32

-2,147,483,648 to2,147,483,647

unsigned long int 32 0 to 4,294,967,295


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Character Types

Character type charisrelated to the integer types Modifiers unsigned and signed can be used char 1 byte(-128 to 127) signed char 1 byte(-128 to 127) unsigned char 1 byte(0 to 255)

Characters are encoded using a scheme where aninteger represents a particular character

ASCII is the dominant encoding scheme(American Standard Code for Information Interchange ) Examples

o ' ' encoded as 32 '+' encoded as 43o 'A' encoded as 65 'Z' encoded as 90o 'a' encoded as 97 'z' encoded as 122

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Floating-Point Types Floating-point types represent real numbers

o Integer parto Fractional part

The number 108.1517 breaks down into the followingpartso 108 - integer parto 1517 - fractional part

C provides three floating-point typeso floato doubleo long double

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floatdouble

long double


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Type Size Range

SinglePrecision float 32 bits4 bytes Numbers between3.4 E-38 and 3.4E+38

Double

Precision

double64 bits8 bytes

Numbers between 1.7E-

308 and 1.7E+308

Long DoublePrecision

long double80 bits

10 bytesNumbers between 3.4E-

4932 and1.1E+4932

SIZE AND RANGE OF VALUES FOR16-BIT MACHINE (FLOATING POINT)


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void

2 uses of void areo To specify the return type of a function when it is not

returning any valueo To indicate an empty argument list to a function

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Logical or Boolean data- named after FrenchMathematician/philosopher George Booleo Consists of only two values: true and falseo Nonzero number can be used to represent trueo Zero is used to represent false

Boolean


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Declaration of variables In order to use a variable in C++, we must first declare it. It does two things

Tells the compiler the variable name. Specifies the type of data.

Primary Type declaration:

write the specifier of the desired data type (like int, char,float...) followed by a valid variable identifier.i.e data-type V1, V2,,Vn ;

For example:int a;float mynumber, sum;


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The integer data types short, longand intcan be eithersignedorunsigneddepending on the range of numbersneeded to be represented.

Signed types can represent bothpositive and negative

values, whereas unsigned types can only representpositive values (and zero).

Declaration of variables


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Signed and unsigned can be specified by using eitherthe specifiersignedor the specifierunsignedbeforethe type name.For example:

unsignedshort int NumberOfSisters;

signedint MyAccountBalance By default most compiler settings will assume the type to

be signed(exception is char).



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Short and long can be used alone as type specifiers.o

The following two variable declarations are equivalent: short Year; short int Year;

Signed and unsigned may also be used as standalone typespecifiers.o

The following two declarations are equivalent: unsigned NextYear; unsigned int NextYear;



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Floating point:keywords float, double, long double Character Type:

keywords char, unsigned char, signed char.

Eg:double deviation;char p, q;



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Assigning values to variables

Values can be assigned using the assignment operator = o It is possible to assign at the time of declaration.

data-type varaiable-name=constant ;int final_value = 100, p = 20;char yes = m;The process of giving initial values to variables Initialization. external & static variables initialized to zero by default. Assigning values to variables after declaration

Eg: initial = 1; area = 23.89;const int class_size= 40;const tells the compiler the value of variable class_size must not modified by

the program. It can be used on the right hand side of any assignmentstatement.

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Initialization of variables example

#include void main (){ int a=5;// initial value = 5int b;b=2;// initial value = 2int result;// initial value undetermineda = a + 3;result = a - b;cout


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User defined Type declarations

typedefo Type definition - lets you define your own type

identifiers.

enumo Enumerated data type - a type with restricted set of

values.

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User defined Type Declaration typedef: general declaration format

typedeftypeidentifier;The type refers to an existing data type and identifier refersto the new name given to the data type.

After the declaration, we can use the identifier to declare variables.

typedefintmarks;typedeffloatunits;marks m1,m2; //m1 & m2are declared as integer variablesunits u1, u2;//u1 & u2are declared as floating point variablesThe main advantage of typedef is that we can create meaningful data type

names for increasing the readability of the program.

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User defined Type Declaration

enum data type :general declaration formatenum identifier {value1, value2,..,valuen};

The identifier is a user defined enumerated data typewhich can be used to declare variables that can have one

of the values known as enumeration constants.After this declaration as follows:enum identifier v1,v2,vn;

enumerated variables v1,v2,..,vn can only have one of the

values value1, value2,,valuen

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User defined Type DeclarationE.g.:enumday {Mon, Tue, Wed, Thu, Fri, Sat, Sun} ;enum day week_st, week_end, Today;week_st = Mon;week_end= Sat;if(Today== Fri) cout


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cout>i;switch(i){

case Monday:cout


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Review of Data Types

What is a data type? List the different category of data tyes? Name the types under Built-in Data types. Discuss the variations of the following:

int, char, float What is void? Why it is required? How you can declare variables? What is initialization? Why it is required? List the six different steps involved in executing a

program.

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T i l C++ P D l t


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Typical C++ Program DevelopmentEnvironment

Phases of C++Programs:1.Edit

Preprocess Compile Link Load Execute

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1 // Program: first.cpp 2 // My first program in C++. 3 #include 4 5 // function main begins program execution 6 int main() 7 {

8 cout


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// Program: first.cpp// my first program in C++

These are single line comments. All lines beginning with two slash signs (//) are

considered comments They do not have any effect on the behavior of theprogram

The programmer can use them to include shortexplanations or observations within the source code itself.

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Comments


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#include

Lines beginning with a sign (#) are directives for thepreprocessor. They are not regular code lines. directive #include tells the preprocessor to

include the iostream standard header file.

This specific file (iostream.h) includes the declarations of thebasic standard input-output library in C++, and it is includedbecause its functionality is going to be used later.

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void main ()

The main function is the point where all C++ programs starttheir execution, independently of its location within thesource code.

it is essential that all C++ programs have a main function.

The word main is followed in the code by a pair ofparentheses (). That is because it is a function declaration.

Optionally, these parentheses may enclose a list ofparameters within them.

Right after these parentheses we can find the body of themain function enclosed in braces{ }.

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cout


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cin>>Rules

>> known as extraction orget fromoperator. It extracts the value from keyboard & assign it to the

variable on its right.

Integer read

o Ignores/skips leading white space characters (space,tab, new line)

o Begins collecting digits, stops at the first non-digitcharacter (leaving that character in the buffer)

Character reado Ignores/skips leading white space characters (space,

tab, new line)o Reads next character (any valid ASCII character)

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cin>>Rules

String reado Ignores/skips leading white space characters (space,

tab, new line)o Collects characters and stops at the first white space

characterE.g.:cin>>a;

cin>>b>>c;

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cout


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1 // Program: Second.cpp

2 // Printing a line with multiple statements.3 #include 45 // function main begins program execution6 int main()7 {

8 cout


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1 // Program: third.cpp

2 // Printing multiple lines with a single statement3 #include 45 // function main begins program execution6 int main()7 {8 cout


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1 // Program: Add.cpp2 // Addition program.3 #include 45 // function main begins program execution6 void main()

7 {8 int integer1; // first number to be input by user9 int integer2; // second number to be input by user10 int sum; // variable in which sum will be stored1112 cout > integer1; // read an integer

1415 cout > integer2; // read an integer1718 sum = integer1 + integer2; // assign result to sum1920 cout


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Algorithm : read and display a no.

Step1: Read a no.

Step 2: [display it on the screen]Print the no. is =, no.

Step 4: [End of algorithm]

Stop

WAP to read and display a number

Input a no.

Print theno.

Start

Stop

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#include // header file for input/output#include// header file for clrscr() & getch()void main()//main function{//program body begins

clrscr();//in-built functionint a;//variable declarationcouta;// reading or input value to the variablecout


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To convert seconds into minutes & seconds To convert Celsius to Fahrenheit & vice versa

Write C++ Programs

[algorithm, flowchart & program]


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Algorithm : conversion of secs into hr, min, secs

Step1: Read secs

Step 2: [do conversions]

hr= sec/3600sec=sec mod 3600min= sec/60sec= sec mod 60Step 3: print hours= hr, minutes= min, seconds= sec

Step 4: [End of algorithm]Stop

WAP to convert seconds into hours,minutes & seconds

hr= sec/3600min= (sec mod 3600)/60

sec= (sec mod 3600) mod 60

Input sec

Print hr, minand sec

Start

Stop

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P t t t d i t


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#include

#includevoid main( ){int sec, hr, min;coutsec;hr= sec/3600; sec = sec % 3600;min= sec/60;sec= sec % 60;cout


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Algorithm : To convert Celsius to Fahrenheit & vice versaStep1: Read celsiusStep 2: Fahrenheit =(9.0 / 5.0) * celsius + 32.0Step 3: Print temp in Fahrenheit= FahrenheitStep 4: Read FahrenheitStep 5: celsius =(Fahrenheit 32) * (5.0 / 9)Step 6: Print temp in celsius= celsiusStep 7: Stop

WAP to convert Celsius toFahrenheit & vice versa

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Fl h t


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Flowchart

Read Celsius

Fahrenheit =(9.0 / 5.0) * celsius + 32.0

print Fahrenheit

Read Fahrenheit

celsius =(Fahrenheit 32) * (5.0 / 9)

Print Celsius

Start

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#include#includevoid main() {float faren , cel;coutcel;faren=(9.0 / 5.0) * cel + 32.0;cout


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To exchange memory variable a and b To display a triangle of * on the screen Find the sum of digits of a 4-digit number

Write C++ Programs

Program to exchange memory


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# include# includevoid main( ) {int a,b;couta;

cin>>b;a=a + b;b=a-b;a=a-b;cout


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#include#includevoid main(){clrscr();

cout


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#include#includevoid main(){clrscr();int num, digit, sum=0;coutnum;digit= num%10;sum=sum + digit;num=num/10;

digit= num%10;num=num/10;sum=sum + digit;digit= num%10;num=num/10;sum=sum + digit + num;cout


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Try the Following problems

1. Write a C++ program to read the price of an item indecimal form(like 15.95) and print the output in paise(like1595 paise).

2. Write a C++ program to covert distance in mm to cm,

inch, feet (1 cm =10mm, 1inch=2.5cm, 1 feet =12 inches).

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