ASD Pb 21 cautare binara

/** p21 cautare binara*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<iostream>
using namespace std;

int BinarySearch2(string cheie, string a[], int prim, int ultim) {
    if(prim>ultim) {
        return -1;
    }
    int x=(ultim-prim)/3;
    int mij1=prim+x;
    int mij2=prim+2*x/3;
    if(cheie==a[mij1]) {
        return mij1;
    } else {
        if(cheie==a[mij2]) {
            return mij2;
        }
    }
    if(cheie<a[mij1])
        return BinarySearch2(cheie, a,prim, mij1-1);
    if(a[mij1]<cheie && cheie<a[mij2]) {
        return BinarySearch2(cheie, a,mij1+1, mij2-1);
    } else {
        return BinarySearch2(cheie, a, mij2+1, ultim);
    }
}
int FindStringInSortedArray(string cheie, string a[], int n) {///functie wrapper
    return BinarySearch2(cheie,a,0,n-1);
}

int main() {
    int n=6;
    string cheie;
    string a[6]= {"a","b","c","d","e","f"};
    cout<<"Dati cheia"<<endl;
    cin>>cheie;

    int index=FindStringInSortedArray(cheie,a,6);
    cout<<" Cheia se gaseste pe pozitia:  "<<index;
    return 0;

}