Data Types In C

//short char sc; //Invalid ..compilation error

//long char lc; //Invalid ..compilation error

//short float f; //Invalid ..compilation error

//short double sd; //Invalid ..compilation error

signed float sf; //Invalid ..warning only//size =4 bytes

unsigned float usf; //Invalid ..warning only//size =4 bytes

signed double sd; //Invalid ..warning only //size =4 bytes

unsigned double usd;//Invalid ..warning only//size =4 bytes

int                       4

char                    1

float                    4

double                8

short int              2

long int               4

long float            8

long double        8

__int16              2

__int32              4

__int64              8

__int8                1

__int16              2

__int32              4

__int64              8

10.1f                   4   //float

10.1F                  4   //float

10.1l                   8   //double

10.1L                  8   //Long double 

long long longlong; //8 bytes

long long int longlongint; //8 bytes

long long char longlongchar; //Invalid ..error

long long float longlongfloat; //Invalid ..error

long long double longlongdouble; //Invalid ..error

To sort an Sorted array which both first half and second half are sorted.

Question: Given an integer array of which both first half and second half are sorted. Write a function to merge the two parts to create one single sorted array
in place [do not use any extra space].
e.g. If input array is [1,3,6,8,-5,-2,3,8] It should be converted to: [-5,-2,1,3,3,6,8,8]
------------------------------------------------------------------------------------------------------

int* SortedArr(int b[],int n)
{
int mid=n/2;
int temp=0;
for(int i=0;i<mid;i++)
{
for(int j=n-1;j>=mid;j--)
{
if(b[i]>b[j])
{
temp=b[i];
b[i]=b[j];
b[j]=temp;
}
}
}
return b;
}

---------------------------------------------------------

This function will return in sorted array 

The main function will be like this

int* SortedArr(int*,int);
void main()
{


int b[8]={1,3,6,8,-5,-2,3,8};
SortedArr(b,8);
printf("\n");
for(int i=0;i<8;i++)
{
printf("%d\n",*(b+i));
}

}

Bubble Sort in C

#include<stdio.h>
#include<conio.h>
#include<malloc.h>
#define N 10
int * BubbleSort(int*, int);
void main()
{

int a[10]={3,7,8,5,2,1,9,5,4,11};
//new sorted array
SelectionSort(a,N);
BubbleSort(a,N);
printf("BUBBLE SORT");
printf("\n");
for(int i=0;i<N;i++)
{
printf("%d\n",*(a+i));
}
_getch();
}

----------------------------------------------------
Bubble sort function
----------------------------------------------------

int* BubbleSort(int  a[],int n)
{
int temp=0;
for(int i=n-2;i>=0;i--)
{
for (int j=0;j<=i;j++)
{
if(a[j]<a[j+1])
{
temp=a[j];
a[j]=a[j+1];
a[j+1]=temp;
}
}
}

return a;
}
----------------------------------------------------------------------------------------------------
output:

Creating a dll in C and how to use it in C++ program

The following Steps are required

1.Create a new project in Visual Studio 2010

2.Under Visual C tab create an empty project

-----------------------------------------------------------------

#include<iostream>
//C++ style header decoration in the dll
  __declspec(dllexport)  int __stdcall add(int a ,int b )
{
return a+b;
}
//c style header declartion in the dll
 extern "C"  __declspec(dllexport) int  _stdcall sub(int a ,int b )
{
return a-b;
}
//C++ style header decoration in the dll
  __declspec(dllexport)int _cdecl mul(int a ,int b )
{
return a*b;
}
//c style header declartion in the dll
extern "C" __declspec(dllexport)int  _cdecl divide(int a ,int b )
{
return a/b;
}

----------------------------------------------------------------------

Before Building the solution change the  solution configration from debug mode to release mode

go to Project property 

in configuration manager change the  configuration to release

In project properties change the configuration type to Dynamic link library(.dll)

--------------------------------------------------------------------------------------------

Build this project. 

there are two types of calling conventions used   (__stdcall)  and   (__cdecl)

By default  the C++ style header decoration is used.

But if we want to use the c style decoration. we will use  extern "C" .

--------------------------------------------------------------------------------------------

To use a C Dll in C++ C project.

Create a C project in Visual studio .

we will use the all function in the dll.

--------------------------------------------------------------------------------------------

#include<iostream>

using namespace std;

//C++ style header decoration in the dll

int __stdcall add(int a ,int b );

//C style header declartion in the dll

extern "C" int  _stdcall sub(int a ,int b );

//C++ style header decoration in the dll

int _cdecl mul(int a ,int b );

//C style header declartion in the dll

extern "C" int  _cdecl divide(int a ,int b );

void main()

{

cout<<add(3,4);

cout<<sub(4,3);

cout<<mul(3,4);

cout<<divide(4,2);

}

-------------------------------------------------------------

In the project property  Go to  VC++ Directories   .In librery Dependencies add the  full path where the dll is placed....

In the linker -->Input-->additional Dependencies -->add the .lib file of the dll generated.

-------------------------------------------------------------------------------------

Compile the .cpp file.

Cholesky decomposition of Matix

To do a Cholesky decomposition the given Matrix Should Be a Symmetric Positive-definite Matrix.

original Matrix

L Matix

Here we have the origianl marix and its cholesky Matrix
A=LLT
LT= Transpose of L Matrix


***************************************************************************



#include<stdio.h>
#include<iostream>
#include<conio.h>
#include<malloc.h>
#include<math.h>

using namespace std;

void main()
{

double a[3][3]={{2,-1,0},{-1,2,-1},{0,-1,2}};
double L[3][3]={0};
double LT[3][3]={0};
int i=0,j=0,k=0;
double temp=0;

for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
temp=0;
if(i==j)
{
for(k=0;k<j;k++)
{
temp+=((L[j][k])*(L[j][k]));
}

L[i][j]=sqrt((double)(a[i][j]-temp));
}

if(i>j)
{
for(k=1;k<j;k++)
{
temp+=((L[i][k]*L[j][k]));
}
L[i][j]=(1/(L[j][j]))*((a[i][j])-temp);
}

if(i<j)
{
L[i][j]=0;
}
}
}



printf("Given Matrixis\n\n");
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
//printf("%2d\t",a[i][j]);
cout<<a[i][j]<<"\t\t\t";
}
printf("\n");
}
// Cheloskey Transform
printf("\nGiven Matrix cheloskey Transform is\n\n");
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
cout<<L[i][j]<<"\t\t\t";
//printf("%f\t",L[i][j]);
}
printf("\n");
}

for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
LT[i][j]=L[j][i];

}
}

printf("\n");
printf("Transpose of L MAtrix is");
printf("\n");
printf("\n");
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
cout<<LT[i][j]<<"\t";
//printf("%2d\t",LT[i][j]);
}
printf("\n");
}

_getch();
}

****************************************************************

The Output will be 

The Input  Matrix Was

The Cheloskey Transform Upper Triangular Matrix is

Its Lower trainguler Matrix is

                                                                                     

Recursion Function to find the Sum of digit of N -Digit Number

#include<stdio.h>
#include<conio.h>

int SumRecursion(int );
void main()
{
int a=0,k=0;
printf("Enter any digit Number");
scanf("%d",&a);
k=SumRecursion(a);
}

int SumRecursion(int num1)
{
int sum=num1;                    //Initialize sum to the current number i.e. num1
sum=num1/10; // Divide The number by 10
int Reminder=num1-sum*10;       //Find the reminder of the number when divided by 10
num1=sum;                        // To use a recursive function we have to keep on   changing the num1 value

if(sum!=0)
{
Reminder=Reminder+SumRecursion(num1);
}
else
return Reminder;
}

Time function in c++

To find the time difference in executing a part of program is done by using functions from (time.h)

it has got mainly two type of time 

1). Calander Time

2) System  Clock time :  It is represented by clock_t() and Clock().

The calender time has a time structure:
This structure contains different type of time data types.
Details of the structure is
struct tm{
              int tm_sec;                /// time in seconds
              int tm_min;              /// time in minute

              int tm_hour;           ///   time in hour

              int tm_mday;            // month day (1-31)

              int tm_mon;             ///month (1-12)

              int tm_wday;          /// days of week;

              int tm_yday;          ///days of year(0-365)

              int tm_year;         ///year 

              int tm_isdst;        ///Daylight Saving Time enabled (> 0), disabled (= 0), or unknown (< 0)

             }