Thread: file reading problem

Originally Posted by but

thanks a lot - pls explain the point of this line -

printf("bad line: j=%d i=%d\n[%s]\n", j, i, line); return EXIT_FAILURE;

Code:

            if (sscanf(line, "%*f %*f %lf %lf %lf", &x, &y, &z) != 3) {
                printf("bad line: j=%d i=%d\n[%s]\n", j, i, line);
                return EXIT_FAILURE;
            }

If sscanf returns 3 it means that it properly read 3 fields. If it doesn't return 3 then something went wrong, so I print an error message and exit. EXIT_FAILURE is just a macro that's equal to a non-zero value appropriate for indicating failure on the system. It's equal to 1 on linux.

By the way after looking at the input file, it looks to me like you shouldn't be discarding the second line of each data set. This line appears to be the number of lines in the data set. This number really should be used in your loops instead of that magic number (13968). This way your program should read the file no matter how many lines are in the data set.

Jim

omg - i was sooooo correct when i said it was hydra headed !!

the monster is still not slain, even after all your inputs - now the last (z) column is getting screwed up =

Pls see the screen shot - all the integers from 0 to 10 are alternately showing up instead of the z value !!1

Originally Posted by jimblumberg

By the way after looking at the input file, it looks to me like you shouldn't be discarding the second line of each data set. This line appears to be the number of lines in the data set. This number really should be used in your loops instead of that magic number (13968). This way your program should read the file no matter how many lines are in the data set.

Jim

my magic number IS that same number. the number is always the same for each set. it need not be read and certainly cannot be written in the final output file.

is there a way to tell from the wrong answer its spitting out as to what the real problem could be - one time it was the position of the x (ie, 4, 8, 12 etc) instead of the value in the 4th, 8th place. SO that is easier to trace- this one is all random - but i think it could be the integer part of the complete value.

i checked - yes its "rounding up" - so every 8.6 is becoming a 9 and so on.

I havent checked to see if those z values where the fraction is less than .5 is getting rounded up or down.

So i am guess this has to be with how its being read - we are reading an decimal number as an integer -

Please show your current code.

Jim

my magic number IS that same number. the number is always the same for each set.

It may be for now, but what if the program generating these data sets is changes to output more or less lines per data set?

it need not be read and certainly cannot be written in the final output file.

The line must be read, and then it can be parsed to replace your magic number still not be written to the final output file.

Jim