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

struct LICE {
    char ime[31]; char EGN[11];
};

FILE *fl;
char imefl[30];
LICE lice;

void readLice(LICE *lc) {
    printf("%20s IME: ","");
    gets(lc->ime);
    printf("%20s ENG: ","");
    gets(lc->EGN);
}

void writeLice(LICE lc) {
    printf("IME: %-21s EGN: %s\n",lc.ime,lc.EGN);
}

int exist(char *ime){
    FILE *f = fopen(ime,"r"); fclose(f);
    return f!=NULL;
}

void szdPrz () {
    char ch;
    if (exist(imefl)) {
        printf("File exists!"); return;
        printf("Rewrite?");
        ch=getchar();
        if (ch == 'n') return;
    }
    fl=fopen(imefl,"w");
    fclose(fl);
    printf("\n File Created. \n");
}

void dobaviane(){
    char ch;
    if (!exist(imefl)) {
        printf("File exists!\n"); return;
    }
    fl=fopen(imefl,"a+b");
    do{
        readLice(&lice);
        fwrite(&lice,sizeof(lice),1,fl);
        printf("Continue?");
        ch=getchar();getchar();
    }
    while (ch != 'n');
    fclose(fl);

}

void iztrivane() {
    FILE *delFl;
    char EGN[11];
    if (!exist(imefl)) {
        printf("File not created!\n"); return;
    }
    printf("EGN: "); gets(EGN);
    fl=fopen(imefl,"rb"); delFl=fopen("Del","wb");
    fread(&lice,sizeof(lice),1,fl);
    while (!feof(fl)) {
        if (strcmp(lice.EGN,EGN) != 0)
        fwrite(&lice,sizeof(lice),1,delFl);
    else printf("Data erased!\n");
    fread(&lice,sizeof(lice),1,fl);
    }
    fclose(fl);fclose(delFl);
    remove(imefl);rename("Del",imefl);
}

void zamiana() {
    char EGN[11];
    if (!exist(imefl)){
        printf("File not created!\n"); return;
    }
    printf("EGN: "); gets(EGN);
    fl=fopen(imefl,"r+b");
    fread(&lice,sizeof(lice),1,fl);
    while (!feof(fl)){
        if (strcmp(lice.EGN,EGN) == 0) {
            readLice(&lice);
            fseek(fl,-(long)sizeof(lice),SEEK_CUR);
            fwrite(&lice,sizeof(lice),1,fl);
            printf("Data rewrited!\n",EGN);
            break;
        }
        fread(&lice,sizeof(lice),1,fl);
    }
    fclose(fl); printf("\n");
}

void spisGod() {
    int k,godTrs,godLice;
    char gg[3];
    if (!exist(imefl)) {
        printf("File not created!\n"); return;
    }
    printf("Year of birth: "); scanf("%d",&godTrs); getchar();
    fl=fopen(imefl,"rb"); k=0;
    fread(&lice,sizeof(lice),1,fl);
    while (!feof(fl)) {
        strncpy(gg,lice.EGN,2); gg[2]=0; godLice=atoi(gg);
        if (lice.EGN[2]>'3') godLice+=2000;
        else godLice+=1900;
        if (godLice==godTrs) {
            k++;writeLice(lice);
        }
        fread(&lice,sizeof(lice),1,fl);
    }
    if (k==0)
    printf("Noone born in %d year!\n",godTrs);
    fclose(fl);
}

void obSpis(){
    int k;
    if (!exist(imefl)){
        printf("File not created!\n"); return;
    }
    fl=fopen(imefl,"rb"); k=0;
    fread(&lice,sizeof(lice),1,fl);
    while (!feof(fl)){
        k++;writeLice(lice);
        fread(&lice,sizeof(lice),1,fl);
    }
    if (k==0) printf("File is empty!\n");
    fclose(fl);
}

void main(){
    int c;
    printf("Filename: "); gets(imefl);
    do {
        printf("%20s Menu:\n");
        printf("%20s 1.Create file'\n'");
        printf("%20s 2.Add entry\n");
        printf("%20s 3.Delete component\n");
        printf("%20s 4.Rewrite component\n");
        printf("%20s 5.Born X year\n");
        printf("%20s 6.List all\n");
        printf("%20s 0.Exit");
        scanf("%d",&c); getchar();
        switch (c) {
            case 1:szdPrz(); break;
            case 2:dobaviane(); break;
            case 3:iztrivane(); break;
            case 4:zamiana(); break;
            case 5:spisGod(); break;
            case 6:obSpis();
        }
    }while (c!=0);
}