getopt not changing value C-CodePudding

This code is supposed to filter a list of students using getopt. It filter's CS, Math and Physics students based on their points. Everything in this switch case works using getopt accept case v which is just supposed to set the value to 1 and filter the list of students so only CS and Math students will be in the list. I don't know why it wouldn't work. I've found multiple examples in books doing it the same way.

I'm sorry I know the code is ugly I tried to make it better for the post.

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h> 
#include "zulassung.h"

int main(int argc, char *argv[]){

int percentageNeededToPassCS = 50; 
int percentageNeededToPassSecondSubject = 50;
int passingMinCS = 0;
int passingMinSecongSubject = 0;
int maxPoints = atoi(argv[1]);
int points;

int studentID;

int CheckV = 0;

char subject[20];
char option;


while((option = getopt(argc, argv,"i:m:v")) != EOF){
    switch(option){
        case 'i':
        percentageNeededToPassCS = atoi(optarg);
        break;
        case 'm':
        percentageNeededToPassSecondSubject = atoi(optarg);
        break;
        case 'v':
        checkV = 1;
        break;
        default: //The default dosen't work yet it's not needed
        printf("Unknown Option: '%s'\n", optarg);
        break;
    }
    argc -= optind;
    argv  = optind;
}

passingMinCS = calculate_pointsneededtopass(maxPoints,percentageNeededToPassCS);
passingMinSecongSubject=calculate_pointsneededtopass(maxPoints,percentageNeededToPassSecondSubject);

printf("\t %d\n", CheckV);
while(scanf("%d %s %d", &studentID, subject, &points) == 3){
    if(checkV == 1){
        if(subject_is_cs_or_math(subject) == 1){
        if(filter_student(passingMinCS,passingMinSecongSubject,checkV,studentID,subject,points) == 1){
        printf("%d\n", studentID);
            }
        }
    }else{
    if(filter_student(passingMinCS,passingMinSecongSubject,checkV,studentID,subject,points) == 1){
        printf("%d\n", studentID);
    }
    }
}

return 0;
}

CodePudding user response：

Setting aside that it's an incomplete piece of program, the thing that is tripping you up is that you've put this inside the while loop.

    argc -= optind;
    argv  = optind;

Move it after the while loop and I think you'll find it works as intended. The printf() in the default: case is unnecessary.