L-34 MCS 275 Wed 4 Apr 2001

/* L-34 MCS 275 Wed 4 Apr 2001 : logging phone calls into file */


/* The program below can be executed with a command line argument.
   This argument is the name of the log file.  If there is no argument,
   then the user will be prompted to specify a file name.
   If the given file already exists, then new data will be added,
   otherwise a new log file will be created.
   After updating, the content of the log file will be printed on screen. */

#include <stdio.h>
#include <string.h>
#include <time.h>

void update ( FILE *log );
/* updates the file and prints the current content */

void print ( FILE *file );
/* prints the content of the file on screen */

int main ( int argc, char* argv[] )
{
   char message[80];
   char filename[80];
   FILE *infile,*logfile;

   printf("\nLogging phone calls into a file.\n\n");
   if (argc > 1)
      strcpy(filename,argv[1]);
   else
   {
      printf("Give the name of the log file : ");
      scanf("%s", filename);
   }

   infile = fopen(filename,"r");        /* check whether file exists */

   if (infile == NULL)
   {
      sprintf(message,"%s%s%s%s%s%s",
         "File \"", filename, "\" does not exist.\n",
         "Will create the file \"", filename, "\".\n");
      logfile = fopen(filename,"w+");   /* open for writing and reading */
   }
   else
   {
      sprintf(message,"%s%s%s%s%s%s",
         "File \"", filename, "\" found.\n",
         "Will append to the file \"", filename, "\".\n");
      fclose(infile);
      logfile = fopen(filename,"a+");   /* open for appending and reading */
   }

   printf("%s", message);
   update(logfile);
   fclose(logfile);
   return 0;

}

void update ( FILE *log )
{
   int area,numb1,numb2;
   float duration;
   time_t current;
   char *timestring;

   printf("\n");
   printf("Give area code : "); scanf("%d", &area);
   printf("first 3 digits : "); scanf("%d", &numb1);
   printf("last 4 digits  : "); scanf("%d", &numb2);
   
   printf("Give duration (minutes.seconds) : ");
   scanf("%f", &duration);

   fprintf(log,"%d %d %d %.2f", area, numb1, numb2, duration);

   current = time(NULL);                /* make a time stamp */
   timestring = ctime(¤t);        /* contains current date and time */
   fprintf(log," %s", timestring);

   rewind(log);
   printf("The current content of the log file :\n");
   print(log);
}

void print ( FILE *file )
{
   char c;

   while (fscanf(file,"%c", &c) == 1)
      printf("%c", c);
}

/* L-34 MCS 275 Wed 4 Apr 2001 : making a phone bill */

/* The program below can take one argument on the command line,
   which contains the logged calls.  If this argument is not given,
   then the user is asked to provide a file name.
   The phone bill is added to the log file.  */ 

#include <stdio.h>
#include <string.h>

void billing ( FILE *bill, float local_rate, float other_rate );
/* the bill is computed with the given rates for local and other calls,
   and is appended to the given file */

void print ( FILE *file );
/* prints the content of the file on screen */

int main ( int argc, char* argv[] )
{
   char message[80];
   char filename[80];
   FILE *infile,*billfile;
   float locrate,othrate;

   printf("\nMaking a phone bill from the logged phone calls.\n\n");
   if (argc > 1)
      strcpy(filename,argv[1]);
   else
   {
      printf("Give the name of the log file : ");
      scanf("%s", filename);
   }

   infile = fopen(filename,"r");        /* check whether file exists */

   if (infile == NULL)
      printf("File \"%s\" does not exist.  Please try again...\n", filename);
   else
   {
      sprintf(message,"%s%s%s%s%s%s",
         "File \"", filename, "\" found.\n",
         "Will append the phone bill to \"", filename, "\".\n");
      fclose(infile);
      billfile = fopen(filename,"r+");  /* open for reading and writing */
      printf("%s\n", message);

      printf("Give rate for local calls : "); scanf("%f", &locrate);
      printf("Give rate for other calls : "); scanf("%f", &othrate);

      billing(billfile,locrate,othrate);

      printf("The phone bill :\n");
      rewind(billfile);
      print(billfile);
      fclose(billfile);
   }

   return 0;
}

void billing ( FILE *bill, float local_rate, float other_rate )
{
   int area,numb1,numb2;
   float duration;
   int c;
   int local = 0;
   float payloc,durloc = 0.0;
   int other = 0;
   float payoth,duroth = 0.0;

   while (fscanf(bill,"%d %d %d %f", &area, &numb1, &numb2, &duration) == 4)
   {
      if (area == 312)
      {
         local++;
         durloc = durloc + duration;
      }
      else
      {
         other++;
         duroth = duroth + duration;
      }
      fscanf(bill,"%*[^\n]");   /* skip rest of the line */
      c = getc(bill);           /* skip the new line symbol */
   }

   while (c = getc(bill) != EOF);  /* skip garbage until EOF */

   fprintf(bill,"Total number of calls : %d\n", local+other);
   fprintf(bill,"  %d local call(s)", local);
   fprintf(bill," for %5.2f minutes", durloc);
   payloc = durloc*local_rate;

   fprintf(bill," at %.2f a minute : $%.2f.\n", local_rate, payloc);
   fprintf(bill,"  %d other call(s)", other);
   fprintf(bill," for %5.2f minutes", duroth);
   payoth = duroth*other_rate;
   fprintf(bill," at %.2f a minute : $%.2f.\n", other_rate, payoth);
   
   fprintf(bill,"Total amount due : $%.2f.\n", payloc+payoth);
}

void print ( FILE *file )
{
   char c;

   while (fscanf(file,"%c", &c) == 1)
      printf("%c", c);
}