C and C++ Programming Forum

Basics of C# : pls help C# program 2 calc power consumtion

Fri, 09 May 2008 13:16:37 +0000

Author: cos130
Subject: pls help C# program 2 calc power consumtion
Posted: 09Â -Â MayÂ -Â 2008 at 13:16

can someone help I need to write a program which can calculate monthly power consumption when given a list of devices together with their power consumption and usage duration in a month and will read from the file and display this information in a user interface in C#.

thanks

C++ : C#:a program to calculate monthly power consumptio

Fri, 09 May 2008 13:09:18 +0000

Author: cos130
Subject: C#:a program to calculate monthly power consumptio
Posted: 09Â -Â MayÂ -Â 2008 at 13:09

hi there

need help urgent.

thanks

C Language : Plz help me with this problem

Thu, 08 May 2008 08:29:14 +0000

Author: zuberi5
Subject: Plz help me with this problem
Posted: 08Â -Â MayÂ -Â 2008 at 08:29

I have to made a Turbo C file which will do this:
firstly, i press print screen button from my keyboard then i will double click the exe of the file i have to make. the exe file will get the captured image from memory and then it will saves it on the hard drive's specific location.

plz help me on how to do it

any logic?????

C++ : Types Of recursion

Wed, 07 May 2008 02:07:52 +0000

Author: asadullah.ansari
Subject: Types Of recursion
Posted: 07Â -Â MayÂ -Â 2008 at 02:07

Detail About Recursion and its Type

Here I am going to give a detail about Recursion in C++.
Definition: Recursion is the process where a function is calleditself but stack frame will be out of limit because function call willbe infinite times. So a termination condition is mandatory to arecursion.
In C++, Recursion can be divided into two types:
(a)   Run- Time Recursion: Normal as in C
(b)   Compile- Time Recursion: By using Template

Each of these can be also divided into following types:

1.   Linear Recursion
2.   Binary Recursion
3.   Tail Recursion
4.   Mutual Recursion
5.   Nested Recursion

1. Linear Recursion: This recursion is the most commonlyused. In this recursion a function call itself in a simple manner andby termination condition it terminates. This process called 'Winding'and when it returns to caller that is called 'Un-Winding'. Terminationcondition also known as Base condition.

Example: Factorial calculation by linear recursion

Run-Time Version


 int Fact(long n)
{
     if(0>n)
               return -1;
    if(0 == n)
       return 1;
    else
{
      return ( n* Fact(n-1));
}
}

Winding Process:

Functioncalled                                 Function return

Fact(6)                                                 6*Fact(5)
Fact(5)                                                 5*Fact(4)
Fact(4)                   4*Fact(3)
Fact(3)                   3* Fact(2)
Fact(2)                   2* Fact(1)
Fact(1)                   1* Fact(0)
Terminating Point
Fact(0)               1

Unwinding Process

Fact(1)               1*1
Fact(2)               2*1
Fact(3)               3*2*1
Fact(4)               4*3*2*1
Fact(5)               5*4*3*2*1
Fact(6)               6*5*4*3*2*1

Compile-Time Version


// template for Base Condition
template <>
struct Fact<0>
{
   enum 
  { 
      factVal = 1 
   };
};

template 
struct Fact
{
   // Recursion call by linear method
   enum
  { 
value = n * Fact::factVal
   };
};

To test it how it's working at compile time, just call
cout << Fact<-1>::factVal ;
And compile it then compiler error will come, because no template for -1.

2. Binary Recursion: Binary Recursion is a process where functionis called twice at a time inplace of once at a time. Mostly it's usingin data structure like operations for tree as traversal, findingheight, merging, etc.

Example: Fibonacci number

Run Time Version Code:


int FibNum(int n)
{
   // Base conditions
      if (n < 1)
         return -1;
      if (1 == n || 2 == n)
        return 1;

   // Recursive call by Binary Method
     return FibNum(n - 1) + FibNum(n -2);   // At a time two recursive function calledso              
                                                                     //   binary
}

Compile Time Version Code


// Base Conditions
template<>
struct FibNum<2>
{
   enum { val = 1 };
};
template <>
struct FibNum<1>
{
   enum { val = 1 };
};

// Recursive call by Binary Method
template 
struct FibNum
{   
   enum { val= FibNum::val + FibNum::val };
};

3. Tail Recursion: In this method, recursive function iscalled at the last. So it's more efficient than linear recursionmethod. Means you can say termination point will come(100%) only youhave to put that condition.

Example: Fibonacci number

Run Time Version Code:


int FibNum(int n, int x, int y)
{   
   if (1 == n)    // Base Condition
   {
      return y;
   }
   else        // Recursive call by Tail method
  {
      return FibNum(n-1, y, x+y);
   }
}

Compile Time Version Code


template 
struct FibNum
{
   // Recursive call By tail method
   enum 
  { 
        val = FibNum::val
   };
};

// Base Condition or Termination 
template
struct FibNum<1, x, y>
{
   enum 
  {
      val = y 
   };
};

4. Mutual Recursion: Functions calling each other.Let's say FunA calling FunB and FunB calling FunA recursively. This isnot actually not recursive but it's doing same as recursive. So you cansay Programming languages which are not supporting recursive calls,mutual recursion can be applied there to fulfill the requirement ofrecursion. Base condition can be applied to any into one or more thanone or all functions.

Example: To find Even Or Odd number

Run Time Version Code:


bool IsOddNumber(int n)
{
   // Base or Termination Condition
   if (0 == n)
      return 0;
   else
      // Recursive call by Mutual Method
      return IsEvenNumber(n - 1);
}

bool IsEvenNumber(int n)
{
   // Base or Termination Condition
   if (0 == n)
      return 1;
   else
      // Recursive call by Mutual Method
      return IsOddNumber(n - 1);
}

Compile Time Version Code



// Base Or Termination Conditions
template <>
struct IsOddNumber<0>
{
   enum 
  {
     val = 0 
  };
};
template <>
struct IsEvenNumber<0>
{
   enum 
  { 
      val = 1 
  };
};

// Recursive calls by Mutual Method

template 
struct IsOddNumber
{
   enum 
  { 
         val = n == 0 ? 0 : IsEvenNumber::val 
   };
};


template 
struct IsEvenNumber
{
   enum 
  { 
       val = n == 0 ? 1 : IsOddNumber::val
  };
};

3. Nested Recursion: It's very different than allrecursions. All recursion can be converted to iterative (loop) exceptnested recursion. You can understand this recursion by example ofAckermann function.

Example: Ackermann function

Run Time Version Code:


int Ackermann(int x, int y)
{
      // Base or Termination Condition
    if (0 == x)
   {
      return y + 1;
 }   
// Error Handling condition
   if (x < 0  ||  y < 0)
  {
      return -1;
   }  
// Recursive call by Linear method 
   else if (x > 0 && 0 == y) 
  {
      return Ackermann(x-1, 1);
  }
   // Recursive call by Nested method
   else
  {
      return Ackermann(x-1, Ackermann(x, y-1));
  }
}

Compile Time Version Code


// Base Or Termination condition
template 
struct Ackermann<0, y>
{
   enum { val = y + 1 };
};

   // Recursive Call by Linear Method
template 
struct Ackermann
{
   enum 
   { 
            val = Ackermann::val
   };
};

// Recursive Call by Nested Method
template 
struct Ackermann
{
   Enum
   { 
         val = Ackermann ::val>::val 
};
};

C++ : How this code works?

Tue, 06 May 2008 22:52:49 +0000

Author: emg
Subject: How this code works?
Posted: 06Â -Â MayÂ -Â 2008 at 22:52

why no one hs answered me .

Graphics in C/C++ : Import an excel chart to a c++ array

Mon, 05 May 2008 07:49:15 +0000

Author: pa
Subject: Import an excel chart to a c++ array
Posted: 05Â -Â MayÂ -Â 2008 at 07:49

Hello!

I have a lot of data that have to be implemented with Visual C++ 2005 express. I'd simply like to import them in an array in order not to have to copy them by hand on this scheme : {0,0,1,5,0,5}.

I did something similar with pictures using templates (function LoadImage).

Maybe there is a library that has functions enabling this process.

Thank you for helping me.

C Language : threads Win32 <-> Linux

Tue, 29 Apr 2008 13:15:25 +0000

Author: JackSparrow
Subject: threads Win32 <-> Linux
Posted: 29Â -Â AprilÂ -Â 2008 at 13:15

Ok, I found the problem/solution but I'm not satisfied:
All works fine when the optimizations in gcc are turned off.
Each optimization (O, O1, O2, O3, Os) will cause an endless loop.

Here an example:

_{#include
#include

int wait1,wait2;

void *mythread(void *ptr)
{
int *parm;
int i;

parm=(int *)ptr;

for (i=0;i<10;i++)
{
    // branch for thread no 1
    if (parm[0])
    {
      printf("\nLoop %i\n",i);
      printf("Thread 1 started and waiting for thread 2 ...\n");
      wait2=0;
      while (wait1);
      wait1=1;

      printf("Thread 1 resumed.\n");
    }
    // branch for thread no 2
    else
    {
      while (wait2);
      wait2=1;
      printf("Thread 2 started and telling Thread 1 to resume ...\n");
      wait1=0;
    }
}

return NULL;
}

int main()
{
pthread_t thr1,thr2;
int parm1[1],parm2[1];

wait1=1;
wait2=1;
parm1[0]=1;
parm2[0]=0;

pthread_create(&thr1,NULL,mythread,(void *)parm1);
pthread_create(&thr2,NULL,mythread,(void *)parm2);

pthread_join(thr1,NULL);
pthread_join(thr2,NULL);

return 0;
}}

C Language : base conversion

Mon, 28 Apr 2008 15:23:38 +0000

Author: JackSparrow
Subject: base conversion
Posted: 28Â -Â AprilÂ -Â 2008 at 15:23

This code could do this from base 2-10 to base 2-10.
There is a nice function called itoa that converts
int to char* and you can specify the base.
Unfortunatelly the function atoi has no base-parameter.
So I recoded it:

#include
#include

int xy(int x,int y)
{
int r=1,i;

for (i=0;i {
    r*=x;
}

return r;
}

int my_atoi(char *s,int base)
{
int r=0,i,j,pos=0;

for (j=0;j<80 && s[j]!=0 && s[j]>='0' && s[j]<='9';j++);

for (i=j-1;i>=0;i--)
{
    r+=(s-'0')*xy(base,pos);
    pos++;
}

return r;
}

int main()
{
char buff[83];
int num,b1,b2;

printf("from base:");
fgets(buff,80,stdin);
b1=atoi(buff);

printf(" to base:");
fgets(buff,80,stdin);
b2=atoi(buff);

printf("Number:");
fgets(buff,80,stdin);
num=my_atoi(buff,b1);

itoa(num,buff,b2);

printf("\nresult is %s\n",buff);

return 0;
}

C Language : Regarding replacing line of code??

Mon, 28 Apr 2008 12:14:36 +0000
Author: JackSparrow
Subject: Regarding replacing line of code??
Posted: 28Â -Â AprilÂ -Â 2008 at 12:14

Sorry, your code looks very strange to me.
Where do you want to place the output-file ?
You opened an input-file for read-only. There you can't make any changes.

Perhaps this should help you:

#include

int main(int argc,char **argv)
{
const int max=1024;
int r=0,i;
FILE *in,*out;
char buff[max+3];

if (argc!=3)
{
    r=1;
    printf("usage: lower \n");
}
else
{
    if ((in=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else
    {
      // Output file will be overwritten when exists !!!
      if ((out=fopen(argv[2],"wb"))==NULL)
      {
        r=3;
        printf("cannot open output-file!\n");
      }
      else
      {
        while (!feof(in))
        {
          buff[0]=0;
          fgets(buff,max,in);

          for (i=0;i!=0 && buff!='\r' && buff!='\n' && (buff==' ' || buff=='\t');i++);

          if (buff=='#')
          {
            for (i=i+1;i!=0 && buff!='\r' && buff!='\n';i++)
            {
              buff=tolower(buff);
            }
          }

          fputs(buff,out);
        }

        fclose(out);
      }

      fclose(in);
    }
}

return r;
}

C Language : Copy/Read/Write a binary file(.mp3)

Mon, 28 Apr 2008 11:42:51 +0000
Author: JackSparrow
Subject: Copy/Read/Write a binary file(.mp3)
Posted: 28Â -Â AprilÂ -Â 2008 at 11:42

Well, that's C++-code.

In C this would look like that:

#include

int main(int argc,char **argv)
{
int r=0,sz;
FILE *f1,*f2;
char buff[4096];

if (argc!=3)
{
    r=1;
    printf("usage: cop \n");
}
else
{
    if ((f1=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else
    {
      if ((f2=fopen(argv[2],"wb"))==NULL)
      {
        r=3;
        printf("cannot open output-file!\n");
      }
      else
      {
        while (!feof(f1))
        {
          sz=fread(buff,1,4096,f1);
          fwrite(buff,sz,1,f2);
        }

        fclose(f2);
      }

      fclose(f1);
    }
}

return r;
}