Something

while(cin>> id >> amount){
        int low=0;
        int high = totalMembers-1;
        int mid = 0;
          

        ClubMember M(id);
        
        while(low < --high){
            mid = (low + high)/2;
            if(memberArr[index[mid]] > M ){
                high = mid;
            }
            else if(memberArr[index[mid]] < M){
                low = mid;
            }
            else if(memberArr[index[mid]] == M){
                memberArr[index[mid]].update(amount);
                cout << id << " " << amount << endl;
                memberArr[index[mid]].print(cout);
                cout << endl;           
            }
            else
                cout << "id not found!" << endl;
            
        }           
            
    }