C Language, Number of columns in an input file!!

Number of columns in an input file!!

Author	Message
s gontie #1 / 5	Number of columns in an input file!! Hi, I would like to create a function able to read from an input file and indicates the number of columns that file contains. The program should read only the first line. If the input file is as follow 120 10 20 24 100 15 39 87 etc... Then, I want to return the int value columns equals to four. The columns should be separated by the caracter space ' '. Have you got some ideas how I could do the job? Thanks a lot for your advice.
Mon, 05 Nov 2001 03:00:00 GMT

Lawrence Kir #2 / 5	Number of columns in an input file!! Quote: >Hi, >I would like to create a function able to read from an input file and >indicates the number of columns that file contains. The program should >read only the first line. >If the input file is as follow >120 10 20 24 >100 15 39 87 >etc... >Then, I want to return the int value columns equals to four. The columns >should be separated by the caracter space ' '. >Have you got some ideas how I could do the job? >Thanks a lot for your advice. One approach would be to read a line ijn using fgets(). and the count the fields in a loop with successive calls to strtok(). -- ----------------------------------------- -----------------------------------------
Mon, 05 Nov 2001 03:00:00 GMT

s gontie #3 / 5	Number of columns in an input file!! Quote: > writes: > >Hi, > >I would like to create a function able to read from an input file and > >indicates the number of columns that file contains. The program > should > >read only the first line. > >If the input file is as follow > >120 10 20 24 > >100 15 39 87 > >etc... > >Then, I want to return the int value columns equals to four. The > columns > >should be separated by the caracter space ' '. > >Have you got some ideas how I could do the job? > >Thanks a lot for your advice. > One approach would be to read a line ijn using fgets(). and the count > the > fields in a loop with successive calls to strtok(). > -- > ----------------------------------------- > ----------------------------------------- Thanks. How could I do that loop. Sorry, I am totally stuck Thanks, Cheers
Mon, 05 Nov 2001 03:00:00 GMT

s gontie #4 / 5	Number of columns in an input file!! Quote: > gontier" > > writes: > > >Hi, > > >I would like to create a function able to read from an input file > and > > >indicates the number of columns that file contains. The program > > should > > >read only the first line. > > >If the input file is as follow > > >120 10 20 24 > > >100 15 39 87 > > >etc... > > >Then, I want to return the int value columns equals to four. The > > columns > > >should be separated by the caracter space ' '. > > >Have you got some ideas how I could do the job? > > >Thanks a lot for your advice. > > One approach would be to read a line ijn using fgets(). and the > count > > the > > fields in a loop with successive calls to strtok(). > > -- > > ----------------------------------------- > > ----------------------------------------- I tried this and it's working. #define MAXCHARS 300 columns = 0; FILE input; char currtoken; i = 0; input = fopen ("data.dat", "r"); fgets(line, MAXCHARS, input); currtoken = strtok (line, " "); while ( (i<8) && (currtoken != NULL) ) { columns++; currtoken = strtok (NULL, " "); } fclose(input); It's the best way to do it????
Mon, 05 Nov 2001 03:00:00 GMT

Lawrence Kir #5 / 5	Number of columns in an input file!! ... Quote: >I tried this and it's working. >#define MAXCHARS 300 >columns = 0; >FILE input; >char currtoken; >i = 0; >input = fopen ("data.dat", "r"); > fgets(line, MAXCHARS, input); Don't forget to check the return values of nboth these functions for failure. Quote: > currtoken = strtok (line, " "); Consider making that currtoken = strtok (line, " \n"); so that the new-line read in by gets will be considered as a separator rather than part of a token. Quote: > while ( (i<8) && (currtoken != NULL) ) > { > columns++; > currtoken = strtok (NULL, " "); Similarly currtoken = strtok (NULL, " \n"); Quote: > } i never seems to get changed here. Are you sure you need i at all? columns looks like it gives you the value you want for the test. Quote: > fclose(input); >It's the best way to do it???? One thing you get to learn in programming is that there is rarely if ever a "best way" to do something. The general approach here is sound however, even if a few details need tidying up. -- ----------------------------------------- -----------------------------------------
Mon, 05 Nov 2001 03:00:00 GMT

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