C # Implementation of the algorithm of binary decimal number in binary and 86 or 16

Binary swap to Decimal method, for example:

Binary number: 11001

Decimal number: 1*2⁴+1*2³+0*2²+0*2¹+1*2⁰=25

Octal to decimal method, for example:

Octal Number: 32007

Decimal number: 3*8⁴+2*8³+0*8²+0*8¹+7*8⁰=13319

Hexadecimal swap method for decimal, for example:

Hexadecimal number: a20f (because the hexadecimal number is represented by a~f between 10~15, so the calculation will a~f with 10~15)

Decimal number: 10*8³+2*8²+0*8¹+15*8⁰=41487

Through the above two or eight, hexadecimal decimal number of the calculation method, you can calculate the code is:

//Parameter Num is the number that needs to be converted, n is the binary of the number 
 public string ToD (string Num, int n) 
 {
 char[] Nums=num.tochararray (); 
 int d = 0; 
 for (int i = 0; I <nums. Length; i++) 
 {
 String number=nums [i]. ToString (); 
 if (n = =) 
 {
 Switch (number.                    ToUpper ()) 
 {
 Case "A": 
 Number = "Ten"; 
 Break                    
 Case "B": 
 Number = "one"; 
 Break                    
 Case "C": 
 Number = "a"; 
 Break                    
 Case "D": 
 Number = ";" 
 Break                    
 Case "E": 
 Number = "number"; 
 Break                    
 Case "F": 
 Number = ";" 
 Break 
} 
} 
 Double power = Math.pow (Convert.todouble (n), COnvert. ToDouble (nums. Length-(i + 1)); 
 D = d + convert.toint32 (number) * CONVERT.TOINT32 (Power); 
} 
 return d.tostring (); 
}