unix fold utility

Quote:

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Originally Posted by itCbitC

Before handing over this assignment the teacher must have covered how to do option processing in class. Hard to believe that she or he would just pull it out of the hat.

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Why? I'm not a computer science prof yet, but it seems like something where you should be able to spot the angles after a few months. I wouldn't want my students to just sleep thru their final project -- I'd have such a big hat they'd love me forever

Quote:

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Originally Posted by MK27

I believe this to be a foolproof and completely optimized way of parsing your particular options:

Code:

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

void wrong () {
        puts("Usage: fold [-s] [-w width] file ...");
        exit (-2);
}

int parse_w (char *arg) {
        int i, retv;
        if (sscanf(arg,"%d",&retv)!=1) wrong();
        return retv;       
}

int main (int argc, char *argv[]) {
        int i, len, sflag=0, width=80;
        FILE *fstRO;
        for (i=1;i<argc;i++) {
                if (strcmp(argv[i],"-s")==0) {sflag=1;continue;}
                if (strncmp(argv[i],"-w",2)==0) {
                        if (strlen(argv[i])>2) {
                                if (sscanf(argv[i], "-w%d",&width)!=1) wrong();
                                continue;}
                        else if (i==argc-1) wrong();
                        width=parse_w(argv[i+1]);
                        i++; continue;
                }
                break;
        }
        if (!(fstRO=fopen(argv[i],"r"))) {
                puts("File not openable");
                return -1;}
        printf("%s opened read-only\n",argv[i]);
        if (sflag==1) puts("-s set");
        printf("width set to %d\n",width);
        fclose(fstRO);
        return 0;
}

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edit: except it doesn't parse the filename...oh well
edit2: okay now it does

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what is int retv in the top function?

If I try to use this as a guide, i'll be pretty lost.

parse_w makes sure the value passed to it is an integer, and returns that integer if so. retv is the integer variable into which the string argument is parsed and which is returned to the caller.

Quote:

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Originally Posted by MK27

Why? I'm not a computer science prof yet, but it seems like something where you should be able to spot the angles after a few months. I wouldn't want my students to just sleep thru their final project -- I'd have such a big hat they'd love me forever

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With a big hat you would even be able to pull off a bunny :D which is in contrast to what a teacher ought to do; perhaps a pointer or a nudge in the right direction. I was curious if something similar had been covered in class. However I would go with something along the lines that tabstop suggested or look at the man page of getopt() to get an idea of how to go about this.

Quote:

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Originally Posted by itCbitC

With a big hat you would even be able to pull off a bunny :D which is in contrast to what a teacher ought to do; perhaps a pointer or a nudge in the right direction. I was curious if something similar had been covered in class. However I would go with something along the lines that tabstop suggested or look at the man page of getopt() to get an idea of how to go about this.

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Hmm...there is a spectrum in that attitude. At one end, the prof could issue a handout and tell everyone that this is their completed assignment they are about to turn in, and explain in detail how they managed to do it. At the other, s/he could just demand an undescribed assignment, then wait until after the assignments had been handed in to explain what was suppose to be done, which I would agree that's not so helpful and could lead someone in just about any direction with very little clue about what the right one might be.

tabstop's suggestion about using switch is definately the thing here. From looking at the assignment, I would say the most complicated part is actually dealing with the options. Since you should be able to optimize beyond what getopts will give you, doing that instead might make a big difference to the whole.

All I have to say is :

http://www.conestogac.on.ca/registra...dishonesty.jsp

Do your assignments yourself. First year is NOTHING compared to the stuff to come. If you're having THAT much trouble I would consider switching to another program because it doesn't get any easier.