how to write a "long" value to a text file?

skorch1

I want to write that "mjd1" value to a text file. I tried it using fprinf() function. but it dint work.

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#include<iostream.h>

#include<conio.h>

#include<dos.h>

#include<stdio.h>

void main()

{

   clrscr();

   FILE *TempFile; 

   int year,day,month,c=1,c1=0;

   char *temp="buf.txt";

   struct date d;

   long double mjd=54832,mjd1,count=0;

   cout<<"\nDay";

   cin>>day;

   cout<<"\nmonth";

   cin>>month;

   cout<<"\nyear";

   cin>>year;

   if(year!=2009)

   {

    for(int j=2009;j<year;j++)

    {   count+=365;

        if(j%4==0)

        c1++;

        cout<<"c1"<<c1;

    }

    }

   if(year%4==0)

   c+=2;

   else c+=3;

   cout<<"\nc2"<<c;

   for(int i=1;i<month;i++)
 
       { if(i==11) c++;

     if(i==4)  c++;

     if(i==6)   c++;

     if(i==9)   c++;
 
       count+=31;

     }

   cout<<"\n Count"<<count;

   cout<<endl;

   mjd1= count + day + mjd - c + c1;

   cout<<"\nModified Julian Date:"<<mjd1;

  TempFile=fopen(temp,"w+");

  fprintf(TempFile,"Modified Julian date%s\t\n",mjd1);

  fclose(TempFile);

  getch();
 
}

donbock

mjd1 is declared as a long double. Are you sure you didn't want it to be a long int? Review the man page for fprintf. The %s conversion specifier is only for use with strings. You need something different for long doubles; and something else again for long ints.

Banfa

Hi Don, IIRC there some weird and complex maths in calculation of julian dates that involves floating point operations. The output should be a long IIRC so mjd1 should cast to a unsigned(?) long for output.

However skorch1 you have used %s which indicates a pointer to a string, I wouldn't be surprised if this program caused a memory access violation. You need to cast mdj1 to unsiged long and use %lu in the fprintf format string and probably read up on format strings.

donbock

In my opinion, the definitive text for all date-related calculations is 'Calendrical Calculations' by Nachum Dershowitz and Edward Reingold. I have the first edition, copyrighted 1997. I see they are up to the 3rd edition now.

how to write a "long" value to a text file?

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