Thread: hex to binary - how do i flush off the leading 0

any idea how do i flush off the leading 0s from my results? I want to start with 1.

import java.util.Scanner; 
 
public class Hex2Bin {
	public static void main(String[] args) {
		String hexStr; 
		int hexStrLen; 
 
		String[] binStrs = {"0000", "0001", "0010", "0011", "0100", "0101", 
							"0110", "0111", "1000", "1001", "1010", "1011", 
							"1100", "1101", "1110", "1111"};
 
		Scanner in = new Scanner(System.in); 
		System.out.print("Enter a Hexadecimal string: "); 
		hexStr = in.next(); 
		hexStrLen = hexStr.length(); 
		System.out.print("The binary equivalent is: "); 
 
		for (int pos = 0; pos <hexStrLen; ++pos){ 
			char hexChar = hexStr.charAt(pos); 
 
			if (hexChar >= '0' && hexChar <='9') {
				System.out.print(binStrs[hexChar-'0']); 
			}else if (hexChar >= 'a' && hexChar <='f'){
				System.out.print(binStrs[hexChar-'a'+10]);
		    }else if (hexChar >= 'A' && hexChar <= 'F'){
		    	System.out.print(binStrs[hexChar-'A'+10]);
		    }else{ 
		    	System.out.println("error: invalid hexadecimal number");
		    	return; 
			}
		}
	}
}

Originally Posted by Norm

If you have a String: "0001" you could use some String methods to find the first "1" and another String method to get the contents of the String from that location to the end of the String.

I understand that i need to use String's indexOf() and substring(). But just how am i gonna insert into my code

i think there is a way to do this without a string.

look into Bitwise and Bit Shift Operators (The Java™ Tutorials > Learning the Java Language > Language Basics)

bitshifting may resolve your problem. i dont remember how my prof did in the pass