Thread: Converting Hex to Decimal

Please post a new topic when you're asking a new question...

I''m assuming that the number being inputted is in a String. In that case, you can use the Integer.parseInt() method;

try
{
Integer.parseInt("3efd",16);
}
catch (NumberFormatException e)
{
     System.out.println("Error! tried to parse an invalid number format");

hehe, I was trying to find the link to it, too

Here it is: Numerical conversion methods

not sure if applicable or not, but this may spark an idea...maybe

Decimal -> hex

String[] allHex = new String[(16*16*16)-1];
 
String key = "0123456789ABCDEFG";
 
for(int i =0, int counter=0 ; i <16; ++i)
    for(int j =0; j <16; ++j)
        for(int k =0; k <16; ++k)
        {
        allHex[counter] = "" + key.charAt(i) +key.charAt(j)+key.charAt(k);
        ++counter;
        }
 
// allHex now holds all hex values from 0 to FFF...for example allHex[123] = "07B"

Maybe you can find a way to work backwards from this

heres another solution to same problem i just solved..using modulus instead this time, and it can convert a single number inputted..instead of generating all values upto desired n
http://www.javaprogrammingforums.com...cimal-hex.html

import java.util.Scanner;


public class N70HexadecimaltoDecimalConverter {

/**
* @param args
*/
//Class for powered
public static int pow(int i, int powerNum) {

return (int) Math. pow( 16, powerNum);
}

public static void main(String[] args) {


Scanner input = new Scanner(System.in);
System.out.print("Enter HexDecimalNumber :" );

String hdN=input.nextLine();
long decNum=0;

for(int i=0;i<hdN.length();i++){
//define the power(exponent)
int powerNum=hdN.length()-i-1;
//extract the chars of String consecutively
int de= hdN.charAt(i);
//format the Hexadecimal to Decimal number
switch(de){
case '0':decNum= 0*pow(16,powerNum)+decNum;break;
case '1':decNum= 1*pow(16,powerNum)+decNum;break;
case '2':decNum= 2*pow(16,powerNum)+decNum;break;
case '3':decNum= 3*pow(16,powerNum)+decNum;break;
case '4':decNum= 4*pow(16,powerNum)+decNum;break;
case '5':decNum= 5*pow(16,powerNum)+decNum;break;
case '6':decNum= 6*pow(16,powerNum)+decNum;break;
case '7':decNum= 7*pow(16,powerNum)+decNum;break;
case '8':decNum= 8*pow(16,powerNum)+decNum;break;
case '9':decNum= 9*pow(16,powerNum)+decNum;break;
case'A':decNum= 10*pow(16,powerNum)+decNum;break;
case'B':decNum= 11*pow(16,powerNum)+decNum;break;
case'C':decNum= 12*pow(16,powerNum)+decNum;break;
case'D':decNum= 13*pow(16,powerNum)+decNum;break;
case'E':decNum= 14*pow(16,powerNum)+decNum;break;
case'F':decNum= 15*pow(16,powerNum)+decNum;break;

}
}
System.out.println("Decimal number is: "+decNum);
}
}