Spektroskopija: teški metali u piću

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

#define MAX_SIMBOL (2 + 1)
#define MAX_SIZE (20 + 1)

typedef struct element_st{
    char simbol[MAX_SIMBOL];
    char ime[MAX_SIZE];
    char vrsta[MAX_SIZE];
    unsigned int a_tezina;
    struct element_st *sl;
}ELEMENT;

void list_init(ELEMENT**);
void delete_list(ELEMENT**);
ELEMENT* make_element(char*,char*,char*,unsigned int);
void add_to_list(ELEMENT**,ELEMENT*);

FILE* safe_open(char*,char*);
void load(FILE*,ELEMENT**);
void save(FILE*,ELEMENT*,char*);

int main(int argc, char** argv){
    if(argc != 4){
        printf("Nepravilno pokretanje programa.");
        return EXIT_FAILURE;
    }else{
        ELEMENT* el;
        FILE*    file = safe_open(argv[2],"r");
        list_init(&el);
        load(file,&el);
        fclose(file);
        file = safe_open(argv[3],"w");
        save(file,el,argv[1]);
        delete_list(&el);
        return EXIT_SUCCESS;
    }
}

void list_init(ELEMENT **glava){
    *glava = NULL;
}

void delete_list(ELEMENT** glava){
    ELEMENT *t;
    while(*glava != NULL){
        t = *glava;
        *glava = (*glava)->sl;
        t->sl = NULL;
        free(t);
    }
}

ELEMENT* make_element(char* t_simbol,char* t_ime,char* t_vrsta,unsigned int t_tezina){
    ELEMENT* new = (ELEMENT*)malloc(sizeof(ELEMENT));
    if(new == NULL){
        printf("Nema dovoljno memorije.");
        exit(EXIT_FAILURE);
    }
    strcpy(new->simbol,t_simbol);
    strcpy(new->ime,t_ime);
    strcpy(new->vrsta,t_vrsta);
    new->a_tezina = t_tezina;
    new->sl = NULL;
    return new;
}

void add_to_list(ELEMENT** glava,ELEMENT* el){
    if(*glava == NULL){
        *glava = el;
    }else{
        ELEMENT* t = *glava;
        while(t->sl != NULL){
            t = t->sl;
        }
        t->sl = el;
    }
    return;
}

 //-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

FILE* safe_open(char* name,char* mode){
    FILE* f = fopen(name,mode);
    if(f == NULL){
        printf("Nemoguce je otvoriti fajl %s.\n",name);
        exit(EXIT_FAILURE);
    }
    return f;
}

void load(FILE* f,ELEMENT** glava){
    char t_ime[MAX_SIZE];
    char t_vrsta[MAX_SIZE];
    char t_simbol[MAX_SIMBOL];
    unsigned int t_tezina;
    while(fscanf(f,"%s %s %u %s",
                                t_simbol,
                                t_ime,
                                &t_tezina,
                                t_vrsta) != EOF){
        add_to_list(glava,make_element(t_simbol,t_ime,t_vrsta,t_tezina));
    }
    return;
}

void save(FILE* f,ELEMENT* glava,char* vrsta){
    ELEMENT* t = glava,
           * s = NULL;
    while(t != NULL){
        fprintf(f,"%-2s %3u %s\n",
                            t->simbol,t->a_tezina,t->vrsta);
        if(strcmp(t->vrsta,vrsta) == 0){
            if(s == NULL){
                s = t;
            }else{
                if(s->a_tezina < t->a_tezina){
                    s = t;
                }
            }
        }
        t = t->sl;
    }
    if(s == NULL){
        fprintf(f,"\nNe postoji element vrste %s.",vrsta);
    }else{
        fprintf(f,"\nNajtezi %s je %s (%s), atomska tezina %u",vrsta,s->ime,s->simbol,s->a_tezina);
    }
    return;
}