Subj : Re: directly inputting numbers
To   : borland.public.cpp.borlandcpp
From : "Michael Fruchter" <mfruchtr@yahoo.com>
Date : Thu Jul 17 2003 10:42 am

Thank you for your response. Am I correct to conclude that
there is no way to directly read in the text as a number? 
(i.e., by telling it to read a certain amount of places) 

Using your example, is it possible to read the file directly 
into the data array (without first reading the file into the
buffer string)?



"Ed Mulroy [TeamB]" <ed@mulroyREMOVETHESECHARS.org> wrote:
>To convert a string to a number with atoi you have to terminate the string
>with a character of value of binary zero (a value of '\0').
>
>Assume that your input is a set of 7, 4-digit numbers without delimiters
>that are read into a string and are destined to be placed into an array.
>Here is a little program which creates a file with that kind of data then
>reads it in.  It does not use a comma, space or other delimiter to separate
>the numbers.  You didn't say if you were working with C or C++ so I wrote it
>as C (but it will also work as C++).
>
>Try it, see that it works.  It is one way to do what you asked.
>
>-------------------------
>#include <stdio.h>
>
>const char testfile_name[] = "testfile.dat";
>
>int ReadTestFile(void)
>  {
>  char buffer[32]; /* deliberately made too big */
>  char  c;
>  int  i;
>  int  iposition;
>  int data[7];
>  FILE *fin = fopen(testfile_name, "r");
>
>  if (fin == NULL)
>      {
>      printf("Error opening test file\n");
>      return 0;
>      }
>
>  fread(buffer, 7 * 4, 1, fin);
>
>  for (i = iposition = 0; i < 7; ++i, iposition += 4)
>      {
>      /* save the next num's char */
>      c = buffer[iposition + 4];
>
>      /* terminate the string */
>      buffer[iposition + 4] = '\0';
>
>      /* read the number into the array */
>      sscanf(buffer + iposition, "%d", &data[i]);
>      /*  or you could have done it this way   */
>      /*  itoa(buffer + iposition, *data[i]);  */
>
>      /* restore the next num's char */
>      buffer[iposition + 4] = c;
>      }
>
>  fclose(fin);
>
>  /* write the data that was read from the file */
>  printf("Data read from the file\n");
>
>  for (i = 0; i < 7; ++i)
>      {
>      printf("Item %d  %d\n", i, data[i]);
>      }
>
>  return 1;
>  }
>
>int CreateTestFile(void)
>  {
>  const char test_data[] = "1111222233334444555566667777";
>
>  FILE *fout = fopen(testfile_name, "w");
>
>  if (fout != NULL)
>    {
>    fwrite(test_data, 28, 1, fout);
>    fclose(fout);
>    return 1;
>    }
>
>  return 0;
>  }
>
>int main()
>  {
>  if (!CreateTestFile())
>    {
>    printf("Error creating test file\n");
>    return 1;
>    }
>
>  ReadTestFile();
>  return 0;
>  }
>-------------------------
>..
>You could have converted it in other ways.  For instance, this will convert
>4 character digits into a number.
>
>
>-------------------------
>  char *p = test_data; /* test_data from the program above */
>  int i;
>  int result = 0;
>
>  for (i = 0; i < 4; ++i)
>    {
>    result = (result * 10) + (test_data[i] - '0');
>    }
>-------------------------
>
>..  Ed
>
>> Michael Fruchter wrote in message
>> news:3f15bd8e$1@newsgroups.borland.com...
>>
>> Is there a way to directly input a number from a non-delimited
>> text as opposed to reading in a certain amount of characters
>> using "fgets" and converting to an integer using "atoi" (and
>> then, if necessary, dividing by 10^x for x decimal places)?
>
>

.