Массив структур. Вышел бесконечный цикл

#include <iostream>
#include <string.h>
#include <math.h>
using namespace std;  
struct vlad{
 
 
char fam[30], im[30], ot[30];   
 int    rus, mat, fiz, ist, god, klass;
    
};
 vlad mas[8];
 int i, num; 
 
 
 void vvod(){ 
 
    cout<<"press fam\n";
    cin>>mas[i].fam;
    cout<<"press name\n";
    cin>>mas[i].im;
    cout<<"press otcheat\n";
    cin>>mas[i].ot;
    cout<<"press klass\n";
    cin>>mas[i].klass;
    cout<<"press year of birthday\n";
    cin>>mas[i].god;
    cout<<"press point of russian\n";
    cin>>mas[i].rus;
    cout<<"press point of math\n";
    cin>>mas[i].mat;
    cout<<"press point of history\n";
        cin>>mas[i].ist;
    cout<<"press point of fizics\n";
        cin>>mas[i].fiz; 
        i++; 
      
    
}
int main(){do
{cout<<"chouse item"<<"\n";
cout<<"1.added pople\n";
cout<<"2. \n";
cout<<"0. close\n";
cin>>num;
switch (num) {
case 1: vvod(); break;
case 2: break;
case 3: break;
case 4: break;}}
while (num!=0);
 
    
}

cin.ignore(1);

dan chel[10];
int p, nomchel;
 
int doba()
{cout<<"\nFamiliy>> "; cin>>chel[nomchel].fam;
cout<<"\nImy>> "; cin>>chel[nomchel].imy;
cout<<"\nOtchestvo>> "; cin>>chel[nomchel].otc;
cout<<"\nData rojdeniy>> "; cin>>chel[nomchel].dat;
cout<<"\nPol(m/w)>> "; cin>>chel[nomchel].pol;
cout<<"\nObrazovanie(v - visshee/s - srednee)>> "; cin>>chel[nomchel].obr;
if (chel[nomchel].obr[0]=='v') {cout<<"\nVUZ>> "; cin>>chel[nomchel].vuz;} else
{cout<<"\nOklad>> "; cin>>chel[nomchel].okl;}
cout<<"\nDomashniy adres>> "; cin>>chel[nomchel].adr;
chel[nomchel].n=1;
nomchel++;  cout<<">>\nChel soxpanen>> "<<nomchel<<"\n";
}