Hi, I'm Vepa!
Swift
Developer

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

typedef struct{
    char registration_number[11];
    int capacity;
    char model[21];
    double wing_span;

}UCAR;

int compare(const void *a, const void *b){
    UCAR **left = (UCAR **)a;
    UCAR **right = (UCAR **)b;

    if((*left)->wing_span != (*right)->wing_span){
        return(*left)->wing_span > (*right)->wing_span ? 1:-1 ;
    } if (strcmp((*left)->model, (*right)->model)){
        return -strcmp((*left)->model, (*right)->model);
    } if((*left)->capacity != (*right)->capacity){
        return ((*left)->capacity - (*right)->capacity);
    }
    return -strcmp((*left)->registration_number, (*right)-> registration_number);
}

int main(int argc, char *argv[]){
    UCAR *flight[240];
    char line[46];

    if (argc <2){
        fprintf(stderr, "birinji argument yok\n");
        return 9;
    }

    FILE *file=fopen(argv[1],"r");

    if(!file){
        fprintf(stderr, "%s file acylmady\n", argv[1]);
        return 5;
    }

    int length = 0;
    while(fgets(line, sizeof(line), file)){
        line[strlen(line)-1] = '\0';
        flight[length] = (UCAR*)calloc(1, sizeof(UCAR));
        strcpy(flight[length]-> registration_number, strtok(line,";"));
        flight[length] -> capacity = atoi(strtok(NULL, ";"));
        strcpy(flight[length]-> model, strtok(NULL, ";"));
        flight[length] -> wing_span = atof(strtok(NULL, ";"));

        length ++;
    }
    fclose(file);

    qsort(flight, length, sizeof(UCAR *), compare);
    if(argc<3){
        fprintf(stderr, "No second argument\n");
        return 9;
    }

    file = fopen(argv[2], "w");
    if(!file){
        fprintf(stderr, "%s cannot opened", argv[2]);
        return 5;
    }

    for(int i=0; i<length; i++ ){
        fprintf(file, "%s;%d;%s;%.2lf\n", flight[i]->registration_number, flight[i]->capacity, flight[i]->model, flight[i]->wing_span);
    }
    fclose(file);

    for (int i = 0; i < length; i++)
    {
        free(flight[i]);
    }

    return EXIT_SUCCESS;
}