I have a homework assignment where I need to do three-way conversion between decimal, binary and hexadecimal. The function I need help with is converting a decimal into a hexadecimal. I have nearly no understanding of hexadecimal, nonetheless how to convert a decimal into hex. I need a function that takes in an int dec and returns a String hex. Unfortunately I don't have any draft of this function, I'm completely lost. All I have is this.
public static String decToHex(int dec)
{
String hex = "";
return hex;
}
Also I can't use those premade functions like Integer.toHexString() or anything, I need to actually make the algorithm or I wouldn't have learned anything.
The easiest way to do this is:
String hexadecimalString = String.format("%x", integerValue);
Here's mine
public static String dec2Hex(int num)
{
String hex = "";
while (num != 0)
{
if (num % 16 < 10)
hex = Integer.toString(num % 16) + hex;
else
hex = (char)((num % 16)+55) + hex;
num = num / 16;
}
return hex;
}
The following converts decimal to Hexa Decimal with Time Complexity : O(n) Linear Time with out any java inbuilt function
private static String decimalToHexaDecimal(int N) {
char hexaDecimals[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
StringBuilder builder = new StringBuilder();
int base= 16;
while (N != 0) {
int reminder = N % base;
builder.append(hexaDecimals[reminder]);
N = N / base;
}
return builder.reverse().toString();
}
A better solution to convert Decimal To HexaDecimal and this one is less complex
import java.util.Scanner;
public class DecimalToHexa
{
public static void main(String ar[])
{
Scanner sc=new Scanner(System.in);
System.out.println("Enter a Decimal number: ");
int n=sc.nextInt();
if(n<0)
{
System.out.println("Enter a positive integer");
return;
}
int i=0,d=0;
String hx="",h="";
while(n>0)
{
d=n%16;`enter code here`
n/=16;
if(d==10)h="A";
else if(d==11)h="B";
else if(d==12)h="C";
else if(d==13)h="D";
else if(d==14)h="E";
else if(d==15)h="F";
else h=""+d;
hx=""+h+hx;
}
System.out.println("Equivalent HEXA: "+hx);
}
}
Here is the code for any number :
import java.math.BigInteger;
public class Testing {
/**
* @param args
*/
static String arr[] ={"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};
public static void main(String[] args) {
String value = "214";
System.out.println(value + " : " + getHex(value));
}
public static String getHex(String value) {
String output= "";
try {
Integer.parseInt(value);
Integer number = new Integer(value);
while(number >= 16){
output = arr[number%16] + output;
number = number/16;
}
output = arr[number]+output;
} catch (Exception e) {
BigInteger number = null;
try{
number = new BigInteger(value);
}catch (Exception e1) {
return "Not a valid numebr";
}
BigInteger hex = new BigInteger("16");
BigInteger[] val = {};
while(number.compareTo(hex) == 1 || number.compareTo(hex) == 0){
val = number.divideAndRemainder(hex);
output = arr[val[1].intValue()] + output;
number = val[0];
}
output = arr[number.intValue()] + output;
}
return output;
}
}
I will use
Long a = Long.parseLong(cadenaFinal, 16 );
since there is some hex that can be larguer than intenger and it will throw an exception
Consider dec2m method below for conversion from dec to hex, oct or bin.
Sample output is
28 dec == 11100 bin
28 dec == 34 oct
28 dec == 1C hex
public class Conversion {
public static void main(String[] argv) {
int x = 28; // sample number
if (argv.length > 0)
x = Integer.parseInt(argv[0]); // number from command line
System.out.printf("%d dec == %s bin\n", i, dec2m(x, 2));
System.out.printf("%d dec == %s oct\n", i, dec2m(x, 8));
System.out.printf("%d dec == %s hex\n", i, dec2m(x, 16));
}
static String dec2m(int N, int m) {
String s = "";
for (int n = N; n > 0; n /= m) {
int r = n % m;
s = r < 10 ? r + s : (char) ('A' - 10 + r) + s;
}
return s;
}
}
Code to convert DECIMAL -to-> BINARY, OCTAL, HEXADECIMAL
public class ConvertBase10ToBaseX {
enum Base {
/**
* Integer is represented in 32 bit in 32/64 bit machine.
* There we can split this integer no of bits into multiples of 1,2,4,8,16 bits
*/
BASE2(1,1,32), BASE4(3,2,16), BASE8(7,3,11)/* OCTAL*/, /*BASE10(3,2),*/
BASE16(15, 4, 8){
public String getFormattedValue(int val){
switch(val) {
case 10:
return "A";
case 11:
return "B";
case 12:
return "C";
case 13:
return "D";
case 14:
return "E";
case 15:
return "F";
default:
return "" + val;
}
}
}, /*BASE32(31,5,1),*/ BASE256(255, 8, 4), /*BASE512(511,9),*/ Base65536(65535, 16, 2);
private int LEVEL_0_MASK;
private int LEVEL_1_ROTATION;
private int MAX_ROTATION;
Base(int levelZeroMask, int levelOneRotation, int maxPossibleRotation) {
this.LEVEL_0_MASK = levelZeroMask;
this.LEVEL_1_ROTATION = levelOneRotation;
this.MAX_ROTATION = maxPossibleRotation;
}
int getLevelZeroMask(){
return LEVEL_0_MASK;
}
int getLevelOneRotation(){
return LEVEL_1_ROTATION;
}
int getMaxRotation(){
return MAX_ROTATION;
}
String getFormattedValue(int val){
return "" + val;
}
}
public void getBaseXValueOn(Base base, int on) {
forwardPrint(base, on);
}
private void forwardPrint(Base base, int on) {
int rotation = base.getLevelOneRotation();
int mask = base.getLevelZeroMask();
int maxRotation = base.getMaxRotation();
boolean valueFound = false;
for(int level = maxRotation; level >= 2; level--) {
int rotation1 = (level-1) * rotation;
int mask1 = mask << rotation1 ;
if((on & mask1) > 0 ) {
valueFound = true;
}
if(valueFound)
System.out.print(base.getFormattedValue((on & mask1) >>> rotation1));
}
System.out.println(base.getFormattedValue((on & mask)));
}
public int getBaseXValueOnAtLevel(Base base, int on, int level) {
if(level > base.getMaxRotation() || level < 1) {
return 0; //INVALID Input
}
int rotation = base.getLevelOneRotation();
int mask = base.getLevelZeroMask();
if(level > 1) {
rotation = (level-1) * rotation;
mask = mask << rotation;
} else {
rotation = 0;
}
return (on & mask) >>> rotation;
}
public static void main(String[] args) {
ConvertBase10ToBaseX obj = new ConvertBase10ToBaseX();
obj.getBaseXValueOn(Base.BASE16,12456);
// obj.getBaseXValueOn(Base.BASE16,300);
// obj.getBaseXValueOn(Base.BASE16,7);
// obj.getBaseXValueOn(Base.BASE16,7);
obj.getBaseXValueOn(Base.BASE2,12456);
obj.getBaseXValueOn(Base.BASE8,12456);
obj.getBaseXValueOn(Base.BASE2,8);
obj.getBaseXValueOn(Base.BASE2,9);
obj.getBaseXValueOn(Base.BASE2,10);
obj.getBaseXValueOn(Base.BASE2,11);
obj.getBaseXValueOn(Base.BASE2,12);
obj.getBaseXValueOn(Base.BASE2,13);
obj.getBaseXValueOn(Base.BASE2,14);
obj.getBaseXValueOn(Base.BASE2,15);
obj.getBaseXValueOn(Base.BASE2,16);
obj.getBaseXValueOn(Base.BASE2,17);
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 1));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 2));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 3));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE2, 4, 4));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,15, 1));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,30, 2));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,7, 1));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE16,7, 2));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 511, 1));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 511, 2));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 512, 1));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 512, 2));
System.out.println(obj.getBaseXValueOnAtLevel(Base.BASE256, 513, 2));
}
}
Check out the code below for decimal to hexadecimal conversion,
import java.util.Scanner;
public class DecimalToHexadecimal
{
public static void main(String[] args)
{
int temp, decimalNumber;
String hexaDecimal = "";
char hexa[] = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
Scanner sc = new Scanner(System.in);
System.out.print("Please enter decimal number : ");
decimalNumber = sc.nextInt();
while(decimalNumber > 0)
{
temp = decimalNumber % 16;
hexaDecimal = hexa[temp] + hexaDecimal;
decimalNumber = decimalNumber / 16;
}
System.out.print("The hexadecimal value of " + decimalNumber + " is : " + hexaDecimal);
sc.close();
}
}
You can learn more on different ways to convert decimal to hexadecimal in the following link >> java convert decimal to hexadecimal.
Simple:
public static String decToHex(int dec)
{
return Integer.toHexString(dec);
}
As mentioned here: Java Convert integer to hex integer
Another possible solution:
public String DecToHex(int dec){
char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F'};
String hex = "";
while (dec != 0) {
int rem = dec % 16;
hex = hexDigits[rem] + hex;
dec = dec / 16;
}
return hex;
}
I need a function that takes in an int dec and returns a String hex.
I found a more elegant solution from http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html . I changed a bit from the original ( see the edit )
// precondition: d is a nonnegative integer
public static String decimal2hex(int d) {
String digits = "0123456789ABCDEF";
if (d <= 0) return "0";
int base = 16; // flexible to change in any base under 16
String hex = "";
while (d > 0) {
int digit = d % base; // rightmost digit
hex = digits.charAt(digit) + hex; // string concatenation
d = d / base;
}
return hex;
}
Disclaimer: I ask this question in my coding interview. I hope this solution doesn't get too popular :)
Edit June 17 2016 : I added the base variable to give the flexibility to change into any base : binary, octal, base of 7 ...
According to the comments, this solution is the most elegant so I removed the implementation of Integer.toHexString() .
Edit September 4 2015 : I found a more elegant solution http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html
Source: Stackoverflow.com