oop ext2_b

#include<iostream.h>

class dat
{
public:
    int code;
    char nm[20];
    int cost;
};

int main()
{
    int t=0,sum=0,a,i=0,count=0,c,flag=0,j,x;
    dat b[50];
    do{
    cout<<"You can do the following, enter appropriate number:\n";
    cout<<"1.Add an item\n";
    cout<<"2.Display total value\n";
    cout<<"3.Delete an item\n";
    cout<<"4.Display all items\n";
    cout<<"5.Quit\n";
    cout<<"What is your choice\n";
    cin>>a;
    cout<<"\n";
    switch(a)
    {
    case 1:
        count++;
        cout<<"Enter the item name\n";
        cin>>b[i].nm;
        cout<<"Enter the item code\n";
        cin>>b[i].code;
        cout<<"Enter the item cost\n";
        cin>>b[i].cost;
        cout<<"\n";
        i++;
        break;

    case 2:
        sum=0;
        cout<<"code\tcost\n";
        for(j=0;j<count;j++)
        {
            cout<<b[j].code<<"\t"<<b[j].cost<<"\n";
            sum=sum+b[j].cost;
        }
        cout<<"\nTotal cost="<<sum<<endl<<"\n";
        break;

    case 3:
        cout<<"Enter the item code to delete the item\n";
        cin>>c;
        for(j=0;j<count;j++)
        {
            if(b[j].code==c)
            {
                flag=1;
                i--;
                cout<<"Item has been deleted\n";
                for(x=j;x<count-1;x++)
                    b[x]=b[x+1];
                cout<<"\n";
                count--;
                break;
            }
            else
                flag=0;
        }
        if(flag==0)
            cout<<"code not found\n\n";
        break;

    case 4:
        cout<<"the items in the list are:\n";
        cout<<"code\tname\n";
        for(j=0;j<count;j++)
            cout<<b[j].code<<"\t"<<b[j].nm<<endl;
        cout<<endl;
        break;

    case 5:
        t=1;
        break;

    default:
        cout<<"invalid operator\n\n";
        break;
    }
    }while(t!=1);
    return 0;
}