Convertir un nombre d'une base vers une autre base en C

#include < stdio .h=""> 
long convertInBase10 (long n, int base)
{
 long quotient = n / 10; 
 Rest = n % 10; 
 if (Quotient == 0)
 return bleibt; 
 else
 return convertingBase10 (Quotient, Basis) * Basis + Rest; 
}
long convertEnBase2 (long n, int base)
{
 long quotient = n / 2; 
 Rest = n % 2; 
 if (Quotient == 0)
 return bleibt; 
 else
 return convertEnBase2 (Quotient, Basis) * Basis + Rest; 
}

long convertInBase4 (long n, int base)
{
 long quotient = n / 4; 
 Rest = n % 4; 
 if (Quotient == 0)
 return bleibt; 
 else
 return convertenBase4 (Quotient, Basis) * Basis + Rest; 
}

long convertInBase8 (long n, int base)
{
 long quotient = n / 8; 
 langer Rest = n % 8; 
 if (Quotient == 0)
 return bleibt; 
 else
 return convertenBase8 (Quotient, Basis) * Basis + Rest; 
}

long convertInBase16 (long n, int base)
{
 long quotient = n / 16; 
 langer Rest = n % 16; 
 if (Quotient == 0)
 return bleibt; 
 else
 return convertingBase16 (Quotient, Basis) * Basis + Rest; 
}

int main() {
 long n = 17; 
 int base = 10; 
 //Dezimal --> base(2,4,8,16)
 printf ("%ld zur Basis %2d = %ld zur Basis 2\n",n, base, convert to Base2 (n, base); 
 printf ("%ld zur Basis %2d = %ld zur Basis 4\n",n, Basis, in Basis 4 konvertieren (n, Basis); 
 printf ("%ld zur Basis %2d = %ld zur Basis 8\n",n, Basis, in Base8 konvertieren (n, base) ); 
 printf ("%ld zur Basis %2d = %ld zur Basis 16\n",n, Basis, konvertieren inBase16 (n, base); 
 
 //Binär --> Dezimal
 n = 1010; 
 = 2; 
 printf ("%ld zur Basis %2d = %ld zur Basis 10\n",n, Basis, in Basis 10 konvertieren (n, Basis); 
 
 //hexadezimal --> Dezimal
 n = 124; 
 = 16; 
 printf ("%ld zur Basis %2d = %ld zur Basis 10\n",n, Basis, in Basis 10 konvertieren (n, Basis); 
 
 //base 8 --> binär
 n = 12; 
 = 8; 
 printf ("%ld zur Basis %2d = %ld zur Basis 10\n",n, Basis, in Basis 10 konvertieren (n, Basis); 
 
 0 zurückgeben; 
}