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

typedef struct elem
{
    char nev[32];
    int magassag;
    char kod[5];
}ELEM;

int rendez (const void *a, const void *b)
{
    ELEM *pa=(ELEM*)a;
    ELEM *pb=(ELEM*)b;

    if (pa->magassag < pb->magassag) return 1;
    if (pa->magassag > pb->magassag) return -1;
    return 0;
}

int main(int argc, char *argv[])
{
    FILE *be, *ki;

    be=fopen(argv[1], "rb");
    ki=fopen(argv[2], "wb");

    int db=0, i;
    ELEM tmp;

    while (fread(&tmp, sizeof(ELEM), 1, be))
        if (strcmp(tmp.kod, argv[3])==0)
            db++;

    ELEM t[db];
    i=0;

    rewind(be);

    while (fread(&tmp, sizeof(ELEM), 1, be))
        if (strcmp(tmp.kod, argv[3])==0){
            strcpy(t[i].nev, tmp.nev);
            t[i].magassag=tmp.magassag;
            strcpy(t[i].kod, tmp.kod);
            i++;
        }
    qsort(t, db, sizeof(ELEM), rendez);

    for (i=0; i<db; i++)
        fwrite(&t[i], sizeof(ELEM), 1, ki);


    fclose(be);
    fclose(ki);

    return 0;
}