//Jordan Steffen
//stej4019 - cs201-807
//prog12.cc
/*purpose: ask user to enter values then convert
number in given base to its base 10 equivalent
and display a reasonable report.*/

#include <iostream>
#include <cmath>
using namespace std;

void welcome();
bool isDigit(char c);
int digit2Int(char c);
int isValidDigit(char c, int base);


int main()
{

  welcome();

  double base;
  cout<<"Please enter the number's base [2, 10] : ";
  cin>>base;
  while(!(base >= 2 && base <= 10))
    {    cout<<"Please enter the number's base [2, 10] : ";
      cin>>base;

    }

  double counter = 0;
  int sum=0;
  char noTest = 'y';
  while(counter < 6)

    {

      char i = 0;
      cout<<"Please enter digit "<<counter<<" [0, "<<base - 1<<"] : ";
      cin>>i;

                while(isValidDigit(i, base) == -1)
                {
                cout<<"Invalid Digit!"<<endl<<endl;
                cout<<"Do you wish to re-enter digit "<<counter<<" (y | n) ? ";

                cin>>noTest;
                if(noTest == 'n')
                        {
                        counter = 6;
                        }
                else
                {
                cout<<"Please enter digit "<<counter<<" [0, "<<base - 1<<"] : ";
                cin>>i;
                }
}

if(isValidDigit(i, base) != -1)
{

        sum += isValidDigit(i, base) * pow(base, counter);
}


      counter += 1;
    }
cout<<"The resulting number in base 10 = "<<sum<<endl;

  return 0;
}


void welcome()
{
  cout<<endl<<"-----------------------------------------------------"<<endl<<
"  Welcome to the CS201 exam base conversion program"<<endl<<
"-----------------------------------------------------"<<endl<<endl<<
"You will first be asked for the base of your number"<<endl<<
"which must be between 2 and 10 inclusive."<<endl<<endl<<
"Next You will repeatedly be asked to enter the digits"<<endl<<
"of your number (right to left).  If you enter a"<<endl<<
"non-digit you will be given the opertunity to either"<<endl<<
"re-enter the mistaken digit or quit the data entering"<<endl<<
"and proceed to the report."<<endl<<
"------------------------------------------------------"<<endl<<endl;
}

bool isDigit(char c)
{
  return ((c >= '0') && (c <= '9'));
}

int digit2Int(char c)
{
  return (c - '0');
}

int isValidDigit(char c, int base)
{
  if(isDigit(c))
    {
      if(base > digit2Int(c))
        return digit2Int(c);

    }
        return -1;
}