C Language

1C Language >Developed by Dennis Ritchie in AT & T’s Bell Laboratories of USA in 1972. AT & T > American Telephone & Telegraph CompanyFeatures > Simple, Portable, Mid Level Programming Lang., Structured Prog. Lang., have Rich Library, do Memory Management, Fast Speed Language, Use Pointers & Arrays, Use Recursion, Its ExtensiblePortable (Program can run on any m/c which support C), Mid Level Programming Lang. (feature of both low level & high level lang.), Structured Prog. Lang. (can be divide in small logical functional module), Arrays (One Varialble can store multiple values of same data types in Consecutive Memory Address), Pointers (is a variable that store the value of other variable), Recursion (the form of function that calls itself where one of the instructions repeat the process), Extensible (can expand from its initial state)Complier built in C, Drivers built in C, OS parts built in C, Embedded Chip programs built in C & Many more.Program Execution : Source Code (.c File) > Complier build object File by linking libraries (.obj File) > Then during run time (.exe file) built in the same folder where source code file placed 
2Types of Languages >Low Level, Mid Level & High Level >Low Level: Machine understandable, Middle Level: features of both languages like C programming which direct access system registry and memory and also its source code is human understandable, High Level: Human understandable language (uses GUI & m/c code independent)C Parts used in learning of other Language >Classes, Objects, Inheritance, Polymorphism, Templates, Exception Handling, References etc Polymorphism > means many forms, when there is hierarchy of classes and related by inheritance. Call to member fx. Will cause diff. fx to execute
3Program Layout >Header Files > Header > Content > Footer
4Object
5Object Oriented Programing Structure >is a programming concept that works on the principle that objects are the most important part of your program. It allows users to create the objects that they want and then create methods to handle those objects.
6Variable
7ConsistsAlphabets, Digits, Special SymbolsConstants, Variables, KeywordsInstructions / StatementsProgram
8Constants >Primary Constant >Integer, Real, Character >Real Constant are called floating points, is in fractional (-+ 32.32) & in  Exponential Form (32e-58, Left of e is Mantisa & Right is Exponent)Character Constant form > ‘a’ or ‘5’ or ‘=’Integer range for 16 Bit compiler = -+32768, more for 32 bit compiler
Secondary Constant >Array, Pointer, Structure, Union, Enum
9Variable Name >In Length of 1 to 31 Characters with combination of Alphabets, Digits & _
10Keywords >Are 32 in numberauto, double, break, else, case, enum, char, extern, const, float, continue, for, default, goto, do, if, int, long, register, return, struct, short, signed, sizeof, static, struct, switch, typedef, union, unsigned, void, volatile, while 
11Comments >// Single Line Comment
/*……*/ Anywhere comment
12Function >main () > is the collective name given to set of statements, all statements belong to this main fx. Statements Are enclosed in braces { }{ Statement 1;Use with statement terminator > ;
 Statement 2; }Use with statement terminator > ;
13Display on screen >printf (“format string”, Variable) ;%d – for Integer Output%s – for string Output\n – New line use in printf statement to execute the next step in new line
%f – for float / Real%u – for unsigned Integer Output
%c – for character ‘c’%ld – for long Integer Output
14Taken input from keyboard and store it in variablescanf (“format string”, &Variable) ;
15Types of Instructions >Declaration Instruction >Use =Assignment operator
Arithmetic Instruction >Use Operators, Hierarchy is !, * / %, + -, < > <= >=, == !=, && ||, =Exponentiation > a=Pow (3,2);> 3 raise to power 2.++a; Pre Increment Operator > show result by already adding, a++; Post Increment > show result for next step by adding after showing first result
Control Instruction >Sequence Control >Execute Statements in Sequence >Inner bracket statement runs 1st > { (4(3(2(1) ) ) ) }
Selection / Decision Control >if, else
Repitition / Loop Control >for, do, while
Case Control >Switch
16Decision Control Structure >if > Value comes non zero then it is trueif (this condition is true) execute this statement ;if (expression)
{ Statement 1 ;
Statement 2 ; }
16.2if – else >if (expression)
{ Statement 1 ;
Statement 2 ; }
else
{ Statement 1 ;
Statement 2 ; }
16.3Nested if – elses >if (expression)
{ Statement 1 ;
Statement 2 ; }
elseMore than 1 condition by && i.e. if ((condition) && (condition))
{{ Statement 1;
if (expression)Statement 2;}
{ Statement 1 ;More than 1 condition by && i.e. if ((condition) || (condition))
Statement 2 ; }{ Statement 1;
elseStatement 2;}
{ Statement 1 ;
Statement 2 ; }
}
16.4Another way else – if >if (expression) Statement;Nested :- if ( ) { ;} else { if () { ;} else { ;}}
else if (expression) Statement;if ((Condition 1) && (Condition2)) Statement :
else if (expression) Statement;
else Statement;
16.5Conditional Operator > if — then — else, are sometimes called ternary operators since they take 3 arguments(expression 1 ? Expression 2 : expression 3);int x, y;
y= ( x>5 ? 3 : 4 )This statement will store 3 in y if x > 5 else store 4 in y
17Loop Control Instruction >While >count = 1;
While (count <=3)
{ Statement 1;
Statement 2;
count = count +1; }
17.2for >for (initialise counter ; test counter ; increment counter)for (count=1 ; count <= 3 ; count = count+1)
{ do this :{ Statement 1;
and this ;Statement 2;
and this ; }Statement 3; }
17.3Nesting of Loops >int r, c, sum ;
for ( r=1; r<=3; r++)                                                                          {
for (c=1; c<=2; c++)                                                                         {
sum = r + c ;
printf ( “r = %d c = %d sum = %d\n”, r, c, sum ) ;  }
}
17.4Odd / Infinite loop > do – while >char another ; int num ;
do
{
printf ( “Enter a number ” ) ;
scanf ( “%d”, &num ) ;
printf ( “square of %d is %d”, num, num * num ) ;              printf ( “\nWant to enter another number y/n ” ) ;               scanf ( “Space%c”, &another ) ;
}                                                                                                while ( another == ‘y’ ) ;		< Infinite loop with consent, Can also use for in case of while, space if must before %c to run this program – don’t know why#include <stdio.h>
main()
{
    int a=0;
    do
    {
        printf(“Value of a is = %d\n”,a);
        a++;
    }
    while (a<=4);
}
18Break Statementmain( )                                                                                           {
int i=1, j=1;
while ( i++ <= 100 )                                                                       {
while ( j++ <= 200 )                                                                       {
if ( j == 150 ) break ;
else
printf ( “%d %d\n”, i, j ) ;
}
printf(“i=%d & j=%d\n”, i,j);                                                      }
19Continue Statementmain( )                                                                                           {
int i,j;
for ( i = 1 ; i <= 2 ; i++ )                                                                 {
for ( j = 1 ; j <= 2 ; j++ )                                                                 {
if ( i == j )                                                                                              continue ;
printf ( “\n%d %d\n”, i, j ) ; }
} }
20Case Control Instruction >Switch > The control statement that allows us to make decision from number of choices
switch ( integer expression )                                                    {
case constant 1 :                                                                     do this ;                                                                                 case constant 2 :                                                                      do this ;                                                                                 case constant 3 :                                                                      do this ;
default :
do this ;
}		main()
{
int i = 2 ;
switch ( i )
{
case 1 :
printf ( “I am in case 1 \n” ) ;
        break;
    
    case 2 :
printf ( “I am in case 2 \n” ) ;
break;
        default :
printf ( “I am in default \n” ) ;
}
}		#include <stdio.h>
main()
{
    char optr;
    int a, b, res;
    
    printf(“\nEnter the Operator = \n”);
    scanf(“%c”, &optr);
    
    printf(“Enter the value for a = “);
    scanf(“%d”, &a);
    
    printf(“\nenter the value for b = “);
    scanf(“%d”, &b);
    
    switch (optr)
    {
        case ‘+’:
            res=a+b;
            printf(“\nSum is = %d”,res);
            break;
            
        case ‘-‘:
            res=a-b;
            printf(“\nMinus is = %d”,res);
            break;
            
        case ‘/’:
            res=a/b;
            printf(“\nDiv. is = %d”,res);
            break;
 

        default :
            printf(“\nOnly input operator b/w + – / \n”);
    }
}
21Called & Calling Function >A function is self contained block of statements that perform a coherent task of some kind >Calling Function > By default, data type is intmain ( )#include <stdio.h>
main()
{
    int a,b, sum;
    
    printf(“enter the value for a = “);
    scanf(“%d”, &a);
    
    printf(“\n enter the value for b = “);
    scanf(“%d”, &b);
    
{ message ();                                                                                        printf(“I came back to main now”); }sum=calsum(a,b);
    printf(“\nSum of both the numbers are = %d\n”, sum);
}		calsum a, b here pass on to calsum x, y
Called Function > Its Execute 1stmessage ( )
calsum(x,y)
int x,y;
{
    int z;
    z=x+y;
    return(z);
}		Scope of variable is local to that fx only i.e. z to calsum only i.e. why it is need to return the z to calling fx
{ printf(“I am in message now”);}
21.1If Called Function does not to return any Value then Void Display ( )
{ 
Printf ( );
Printf ( );
}
21.2Clear Screen FunctionClrscr () ;#include <conio.h>                                                       clrscr ( ) ;
main ( )                                                                                 { }
22Preprocessor Directive >It is program that processes our program before it passes to compilerMACROS (#define)#define UPPER 25 main( )
{
int i ;
for ( i = 1 ; i <= UPPER ; i++ )
printf ( “\n%d”, i ) ; }		During preprocessing, the preprocessor replaces every occurrence of UPPER in the program with 25#define AREA(x) ( 3.14 * x * x )                                             main( )
{
float r1 = 6.25, r2 = 2.5, a ;
a = AREA ( r1 ) ;
printf ( “\nArea of circle = %f”, a ) ;                                              a = AREA ( r2 ) ;
printf ( “\nArea of circle = %f”, a ) ;
}		main( )                                                           {
#ifdef OKAY                                     statement 1 ;
statement 2 ; /* detects virus */                                  statement 3 ;
statement 4 ; /* specific to stone virus */
#endif
statement 5 ;                                      statement 6 ;                                  statement 7 ;
}		Here, statements 1, 2, 3 and 4 would get compiled only if the macro OKAY has been defined, and we have purposefully omitted the definition of the macro OKAY. At a later date, if we want that these statements should also get compiled all that we are required to do is to delete the #ifdef and #endif statements.
Header file > (#include)# include <stdio.h >Standard Input / Outpu fx
# include <math.h >Mathematical / Airthmetical fx
# include <conio.h >Console Input / Output fx
Conditional Compilation(#ifdef – #else – #endif, #if and #elif, #undef and #pragma)See above —
23Pointers > (Address of Memory)main( )                                                                                            {
int i=3;
printf ( “\nAddress of i = %u”, &i ) ;                                       printf ( “\nValue of i = %d”, i ) ;
}		Address of i = 65524, Value of i = 3printf ( “\nValue of i = %d”, *( &i ) ) ;&i give address of memory *(&i) gives value stored at that memory address
24Storage ClassesMemory & CPU Registers
25Arrays >Set of similar data types called arrays and stored in consecutive memory locationsIn other words, one variable stores many value at a time is called array array mentioned in [ ] bracketsLet us try to write a program to find average marks obtained by a class of 30 students in a test.
main( )                                                                               {
int avg, sum=0;
int i ;
int marks[30] ; /* array declaration */
for ( i = 0 ; i <= 29 ; i++ )                                                   {
printf ( “\nEnter marks ” ) ;
scanf ( “%d”, &marks[i] ) ; /* store data in array */                                                                                       }
for ( i = 0 ; i <= 29 ; i++ )
sum = sum + marks[i] ; /* read data from an array & add all in sum*/
avg = sum / 30 ;
printf ( “\nAverage marks = %d”, avg ) ;                                                                                }		2D Array :-                                                                                     main( )                                                                                             {
int stud[4][2] ;                                                                               int i,j;
for ( i = 1 ; i <= 4 ; i++ )                                                                  {
printf ( “\n Enter Marks1. and Marks2” ) ;
scanf ( “%d %d”, &stud[i][0], &stud[i][1] ) ;                                                                                                 }
for ( i = 1 ; i <= 4 ; i++ )
printf ( “\n%d %d”, i, stud[i][0], stud[i][1] ) ;
}
26Enum (Enumeration)User defined Data Type >enum month {JAN,FEB,MAR,APR,MAY,JUN,JUL,AUG,SEP,OCT,DEC};
enum month rmonth;
//First Line Creates “User Defined Data Type” called month.

//In the second line “rmonth” variable is declared of type “month” 
rmonth = FEB;
//Default Numeric value assigned to first enum value is “0”
Numerically JAN is given value “0”.
FEB is given value “1”.
MAR is given value “2”.
APR is given value “3”.
MAY is given value “4”.
JUN is given value “5”.
and so on…..
//printf(“%d”,rmonth);
It will Print “1” on the screen because “Numerical Equivalent” of  “FEB” is 1 and “rmonth” is initialized by “FEB”		#include< stdio.h>
void main()
{
int i;
enum month {JAN,FEB,MAR,APR,MAY,JUN,JUL,AUG,SEP,OCT,DEC};
clrscr();
  for(i=JAN;i<=DEC;i++)
      printf(“\n%d”,i);
}
Output : 0 1 2 3 4 5 6 7 8 9 10 11
27.+= & -= Operator >b+=aShow result by already adding a in bSimilarly > *=, /=, %=
b-=aShow result by already substract a in b and show the results in contineous form by preserving earlier value for variable
28Print of Size of Char, float, double, int >printf (” Size of Char %d”, Size of (Char));printf (” Size of float %d”, Size of (float));printf (” Size of double %d”, Size of (double));
29Decimal position limit in float >%.2f
30ASCII ValueA Character variable holds an integer number from 0 to 127 rather then character itself called ASCII Value  #include <stdio.h>
main()
{
    int x = ‘A’;
    printf (” ASCII Value  of A as Character = %c & its Integer value is = %d \n”, x,x);
}		Answer is 65, x is the variable taken to print A Value
31RecursionA function is called ‘recursive’ if a statement within the body of a function calls the same function.Means the set of statements with in the fx called itselfmain( )                                                                                           {
int a, fact ;
printf ( “\nEnter any number ” ) ; scanf ( “%d”, &a ) ;
fact = factorial ( a ) ;
printf ( “Factorial value = %d”, fact ) ;                                                                                           }
factorial ( int x )                                                                            {
int f=1,i;
for ( i = x ; i >= 1 ; i– ) f=f*i;
return ( f ) ;                                                                                              }		And here is the output…
Enter any number 3 Factorial value = 6		main( ) {
int a, fact ;
printf ( “\nEnter any number ” ) ; scanf ( “%d”, &a ) ;
fact = rec ( a ) ;
printf ( “Factorial value = %d”, fact ) ; }
rec ( int x ) {
int f;
if ( x == 1 ) return ( 1 ) ;
else
f = x * rec ( x – 1 ) ;
return ( f ) ; }
32Union
 C++       
1FunctionAlso Called Method, Sub-routine, Procedure etcreturn_data_type function_name(Parameters_data_type Parameters_name)                                                                                                   {                                                                                                  body of the function                                                                                      }In case there is nothing to return by function then use keyword void at place of return data typeIf no any parameters to pass then keep the parameters braces blankCall by Value, Address, Referencesum (a, b) => calsum (x, y), a & b are called arguments and x & y are called parameters
2ArrayOne variable can store multiple Similar data types values in consecutive memory locations, It is data structuredata_type array_name[ size of array in terms of nos]int array[5] or int array[5] = {1, 2, 3, 4, 5}Index start from 0Array can be 1D or 2D like int ar[2][5] / ar[rows][columns]by using :- #include <string>intialize from 0th row & 0th column
3Stringchar array_name[ size of array in terms of nos]char greeting[] = “Hello” or char greeting[6] = {‘H’, ‘E’, ‘L’, ‘L’, ‘O’, ‘\0’}also have sub strings too
4Print at Screencout << “Greeting Message :”;cout << greeting << endl;Result :- Greeting Message : HelloOR cout << “Greeting Message :” << greeting << endl;
5CreatorBjarne Stroustrup in 1980 at Bell LabsIt is extension of C Languages i.e. C languages with classes
6First C++ Program#include <iostream>
using namespace std;

int main()
{
    cout <<” C++ is the Extension of C Language\n\n”;
}
7Program StructureHeader Files :- Global Declaration :-Class Declaration :-Main Function :-Method Definition :-
#include <iostream>                                                                   using namespace std;int main(){
    cout <<” C++ is the extention of C Language\n\n”;
}
OR #include<iostream.h>
8User Input Storingcin >> variable_name;#include <iostream>
using namespace std;

int main()
{
    int num1, num2, sum;
    
    cout <<“Enter the value for num1 = “;
    cin >> num1;
    cout <<“Enter the value for num2 = “;
    cin >> num2;
    
    sum=num1+num2;
    cout <<“Sum of both the numbers are = ” <<sum <<endl;		OR                                                                                            cout <<“Enter the value for num1 2nd time = “;
    cin >> num1;
    cout <<“Enter the value for num2 2nd time = “;
    cin >> num2;
    
    cout <<“Addition of both numbers = ” <<num1+num2;
    cout<<“\n\n”;
}
9New Linecout <<……”\n or ,n”;cout << “My name is nKamal”;cout <<” My name is Kamal” <<endl;
10Library Functionsetw()set the number of characters to be used as field width for inserting#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
    cout <<setw (12);
    cout <<“Kamal9999”;
}		Result :- _ _ _Kamal9999#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
    
int maxcount=4;
int width=6;
int row;
int column;

for(row=1; row<=10; row++)
{
    for(column=1; column<=maxcount; column++)
    {
        cout <<setw (width) << row * column;
    }
    cout <<endl;
}
}		by using :- #include <iomanip>
11Keywordsare 48 in numberasm, auto, break, case, catch, char, class, const, continue, default, delete, double, else, enum, extern, float, for, friend, goto, if, inline, int, long, new, operator, private, protected, public, register, return, short, signed, sizeof, static, struct, switch, template, this, throw, try, typedef, union, unsigned, virtual, void, volatile, while
12Diff. b/w while & do while loopWhileDo – while
It is exit controlled loopIt is entry controlled loop
It execute the statements once and then check loop conditionIt 1st check the loop condition, if it is true then executes the statements
13ContinueSkip the statement next to continue and exit the control to whilefor loop > after continue, increament / decreament statement get executed
while loop > after continue, control goes to condition statement
do – while loop > after continue, control goes to condition statement specified in while
14Breakafter break, Terminate the loop or control give outside of condition
15InheritanceBase class – Main classDerived Class – class doing inheritance and acquires the properties of main classTypes :- Single, Multiple, Multi-Level & Hierarchical, Hybrid
16OverloadingAll values of one object can be copy to other objectReturn_type operator=(const class_name &)#include <iostream>
using namespace std;

class Marks
{
private:
    int m1;
    int m2;
    
public:
    Marks(int i, int j)
    {
        m1=i;
        m2=j;
    }
    
    void operator=(const Marks &M)
    {
        m1=M.m1;
        m2=M.m2;
    }
    
    
void Display()
    {
        cout <<“Marks of 1st Subject : ” <<m1 <<endl;
        cout <<“Marks of 2nd Subject : ” <<m2 <<endl;
    }
};

int main()
{
    Marks Mark1(45, 89);
    Marks Mark2(36, 59);
    
    cout <<“Marks of 1st Student :-” <<endl;
    Mark1.Display();
    cout <<“Marks of 2nd Student :-” <<endl;
    Mark2.Display();
    
    Mark1=Mark2;
    cout <<“Marks of 1st Student :-” <<endl;
    Mark1.Display();
    return 0;

}
17Constructor3 typesDefault, Parameterized, Copy Constructor > Respectively#include <iostream>
using namespace std;

class Marks
{
public:
    int m1;
    int m2;
    
    Marks()
    {
        m1=9;
        m2=9;
    }
    
    void Display()
    {
        cout <<” Math : ” <<m1 <<endl;
        cout <<” Science : ” <<m2 <<endl;
    }
};
    
    int main()
    {
        Marks m;
        m.Display();
        return 0;
    }		#include <iostream>
using namespace std;

class Marks
{
public:
    int m1;
    int m2;
    
    Marks(int i, int j)
    {
        m1=i;
        m2=j;
    }
    
    void display()
    {
        cout <<” Math : ” <<m1 <<endl;
        cout <<” Science : ” <<m2 <<endl;
    }
};

int main()
{
    Marks m(40, 80);
    m.display();
}		#include <iostream>
using namespace std;

class Marks
{
public:
    int m1, m2;
    
    Marks()
    {
        m1= 60;
        m2=70;
    }
    
    Marks (const Marks &obj)
    {
        m1=obj.m1;
        m2=obj.m2;
    }
    
    void display()
    {
        cout <<” Math : ” <<m1 <<endl;
        cout <<” Science : ” <<m2 <<endl;
    }
};

int main()
{
    Marks mx;
    Marks my(const Marks &mx);
    my.display();
    return 0;
18Bitwise Operator
19DestructorFree Memory#include<iostream> 
using namespace std;
 
class Marks
{
public:
   int maths;
   int science;
   
   //constructor
   Marks() {
      cout << “Inside Constructor”<<endl;
      cout << “C++ Object created”<<endl;
   }

   //Destructor
   ~Marks() {
      cout << “Inside Destructor”<<endl;
      cout << “C++ Object destructed”<<endl;
   }
};

int main( )
{
   Marks m1;
   
   cout<<“Hello World !!” <<endl;
   cout<<“Hello World !!” <<endl;
   cout<<“Hello World !!” <<endl;
   cout<<“Hello World !!” <<endl;

   return 0;
}
20ClassScopeMemberObjectObject.MemberAbstract Class
public (class member can access anywhere in program)/ protected (class member can access in inheritance class & in parent class)/ private (class member can only access in parent class)#include <iostream>
using namespace std;

class shape
{
protected:
    int width;
    int height;
    
public:
    void setwidth(int w)
    {
        width = w;
    }
    void setheight(int h)
    {
        height = h;
    }
};

class paintcost
{
public:
    int getcost(int area)
    
{
        return area * 70;
    }
};

class rectangle: public shape, public paintcost
{
public:
    int getarea()
    {
        return (width * height);
    }
};

int main()
{
    rectangle rect;
    int aria;
    
    rect.setwidth(5);
    rect.setheight(6);
    aria = rect.getarea();
    
    cout <<“Total Area : ” <<rect.getarea() <<endl;
    cout <<“Total Paint Cost : $” <<rect.getcost(aria) <<endl;
    return 0;
21Polymorphism
22Data Abstractionexecute result w/o knowing to outer world by a class by hiding implementation detailsData Encapulisation :- is the mechanism to building the data and functions which use them
23Library – fstreamread & write from file >ofstream / ifstream / fstream >creat file & write information to files / read information from file / does both tasksalso have sub-strings
23Dynamic Memory
24Templates
25Namespaces
26Pointer to Array#include <iostream>
using namespace std;

int main()
{
    double ar[5]={10, 20, 30, 40, 50};
    double *ptr;
    
    ptr=ar;
    cout <<“Value of Array Elements are :” <<endl;
    
    for (int i=0; i<5; i++)
    {
    cout <<” *(ptr + ” <<i <<“) : “;
    cout << *(ptr+i) <<endl;
    }
}