Conversions between number systems source code

This snippet submitted by Ali Nawkhas Murad on 2012-05-02. It has been viewed 38220 times.
Rating of 5.9 with 211 votes
//General purpose converter program for conversion between any two number systems.
//As long as there is more than one number system in use, conversion of
//numbers from one system to another is important.
//By this program you can convert number systems with radix more than 16 also.
#include <iostream>
#include <string.h>
using namespace std;
char* low_upper(char* in)
{
    for( int i = 0 ; in[i] != '\0' ; i++)
         if( in[i] >= 'a' && in[i] <= 'z' )
          in[i] = in[i] - 32;
             return in;
}
double convx_d( char* , int );
char* convd_x(double , int, char );

int main()
{
    int i_radix,o_radix;
    double dx;
    char cx;
    char in[65] = {"\n"};
    char out[65] = {"\n"};

    char rad_name[16][14] = {"Unary","Binary","Ternary","Quaternary","Quinary","Senary",
                            "Septal","Octal","Nonary","Decimal","Undecimal","Duodecimal",
                            "triskadecimal","Tetradecimal","pentadecimal","Hexadecimal"};
            in[0] = '\0';
            out[0] = '\0';
    cout << "To EXIT press Ctrl+z : " << endl;
    cout << "Enter Radix for the input number system: ";
    while (cin >> i_radix)
    {
            cout << "Enter Radix for the output number system: ";
            cin >> o_radix;
            cout << "Enter the number: ";
            cin >> in;

           if( i_radix > 10)
              strcpy( in , low_upper(in));

          dx = convx_d( in , i_radix);
            if( in[0] == '-')
               cx = '-';
            else
               cx = '0';
           strcpy(out, convd_x(dx, o_radix, cx));

                cout << "\nThe number (" << in << ") in " << rad_name[i_radix-1] << " number system";
                cout << "\n = (" << out << ") in " << rad_name[o_radix-1] << " number system.";
                cout << "\n\nTo EXIT press Ctrl+z : ";
                cout << "\nEnter Radix number for the input number: ";
                in[0] = '\0';
                out[0] = '\0';
     }
    return 0;
}
double convx_d(char* in , int r)
{
    int i = 0 ,j;
    long lx = 0;
    double dx = 0.0;
    if(in[0] == '-')
        i++;
            while(in[i] != '\0' && in[i] != '.')
            {
                lx = lx * r + ((in[i] >= '0' && in[i] <= '9')? in[i] - 48 : in[i] - 55);
                i++;
            }
            if( in[i] == '.')
            {
               j = i;
               while( in[i] != '\0')//count number of steps after decimal point
                   {
                       i++;
                   }
                    i--;
                    double ir = (double) r;
                while( i > j)
                    {
                       dx =  (dx + ((in[i] >= '0' && in[i] <= '9')? in[i] - 48 : in[i] - 55)) * 1.0/ir;
                        i--;
                    }
            }
            return dx += lx;
}
char* convd_x( double dx , int r, char cx)
{
    int i = 0,j ,temp;
    double fx;
    char ctemp[65] ={"\n"};
    char out[65] = {"\n"};
    long lx = static_cast<long>(dx);
          dx -= lx;
//                   calculation of integer part.
//***************************************************************
          while( lx > 0)
            {
                temp = lx % r;
                ctemp[i] = (temp >= 0 && temp <= 9 )? temp + 48 : temp + 55;
                lx /= r;
                i++;
            }
              ctemp[i] = '\0';
                i--;
                j = 0;
             if( cx == '-')
                 {
                   out[j] = '-';
                   j++;
                 }
              for(  ;  i >=0 ; i--, j++ )
                   out[j] = ctemp[i];
                   out[j] = '\0';

//                   calculation of fraction part.
//***************************************************************
             if( dx > 0.0)
                {
                      out[j] = '.';
                      j++;
                      i = j;
                    while( dx > 0.0000001 && j < i+9)
                        {
                           fx = dx * r;
                           temp = static_cast<int>(fx);
                           ctemp[j] = ((temp >= 0 && temp <= 9 )? temp + 48 : temp + 55);
                            dx = fx - temp;
                               j++;
                        }
                    for(  ;  i <= j ; i++ )
                       out[i] = ctemp[i];
                        out[i] = '\0';
                 }
           return out;
}
/*Program's output
*******************************************
To EXIT press Ctrl+z :
Enter Radix for the input number system: 16
Enter Radix for the output number system: 10
Enter the number: cd56.8

The number (CD56.8) in Hexadecimal number system
 = (52566.5) in Decimal number system.

To EXIT press Ctrl+z :
Enter Radix number for the input number: 8
Enter Radix for the output number system: 16
Enter the number: -723.56

The number (-723.56) in Octal number system
 = (-1D3.B8) in Hexadecimal number system.

To EXIT press Ctrl+z :
Enter Radix number for the input number: 16
Enter Radix for the output number system: 8
Enter the number: -1d3.b8

The number (-1D3.B8) in Hexadecimal number system
 = (-723.56) in Octal number system.

To EXIT press Ctrl+z :
Enter Radix number for the input number: ^Z

Process returned 0 (0x0)   execution time : 92.999 s
Press any key to continue.

*/
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