decimal to binary , decimal to octal , decimal to hexadeciaml conversions and vice versa programs in java

 binary to decimal conversion

code:

import java.util.*;

import java.lang.*;

import java.io.*;

//binary to decimal

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

//take the binary number from the user

int bin = scn.nextInt();

//write the lgic to convert it into decimal

int dec = 0;

int i = 0;//digit place

while(bin!=0){

//last digit

int r = bin%10;

//multiple remaider with 2 power digit place

dec = dec +(r* (int)Math.pow(2,i));

//increment the position of i

i++;

//remove the last digit from the number

bin = bin/10;

}

//print the decimal number

System.out.println(dec);

}

}

ex::

input : 1010

o/p: 10

input : 1000

o/p: 8

octal to decimal Conversion

Code::

import java.util.*;

import java.lang.*;

import java.io.*;

//binary to decimal

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

//take the octal number from the user

int oct = scn.nextInt();

//write the lgic to convert it into decimal

int dec = 0;

int i = 0;//digit place

while(oct!=0){

//last digit

int r = oct%10;

//multiple remaider with 8 power digit place

dec = dec +(r* (int)Math.pow(8,i));

//increment the position of i

i++;

//remove the last digit from the number

oct = oct/10;

}

//print the decimal number

System.out.println(dec);

}

}

ex:

i/p: 30

o/p: 24

i/p:40

o/p: 32

hexadecimal to decimal

code:

import java.util.*;

import java.lang.*;

import java.io.*;

//hexadecimal to decimal

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

System.out.println("Enter the hexadecimal number ");

String hexaString = "0123456789ABCDEF";

String hex = scn.next();

hex = hex.toUpperCase();

int dec = 0;

int pow = 0;

for(int i=hex.length()-1;i>=0;i--){

char ch = hex.charAt(i);

int num = hexaString.indexOf(ch);

dec = dec + ((num)*(int)Math.pow(16,pow));

pow++;

}

System.out.println(dec);

}

}

ex:

i/p: F1

o/p:  241

i/p: F

o/p: 15

Decimal to binary Conversion

Code::

import java.util.*;

import java.lang.*;

import java.io.*;

//decimal to binary

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

System.out.println("Enter the decimal number : ");

int dec = scn.nextInt();

String s = "";

while(dec!=0){

int r = dec%2;

s =  String.valueOf(r) + s;

dec = dec/2;

}

System.out.println(s);

}

}

ex:

i/p : 1010

o/p: 10

i/p: 1000

o/p: 8

Decimal to Octal Conversion

Code::

import java.util.*;

import java.lang.*;

import java.io.*;

//decimal to octal

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

System.out.println("Enter the decimal number : ");

int dec = scn.nextInt();

String s = "";

while(dec!=0){

int r = dec%8;

s =  String.valueOf(r) + s;

dec = dec/8;

}

System.out.println(s);

}

}

ex:

i/p: 40

o/p: 50

Decimal to HexaDecimal

Code::

import java.util.*;

import java.lang.*;

import java.io.*;

//decimal to hexadecimal

class Test {

public static void main(String[] args){

Scanner scn = new Scanner(System.in);

String hexaString = "0123456789ABCDEF";

System.out.println("Enter the decimal number : ");

int dec = scn.nextInt();

String s = "";

while(dec!=0){

int r = dec%16;

if(r>9){

char ch = hexaString.charAt(r);

s = ch + s;

}else{

s =  String.valueOf(r) + s;

}

dec = dec/16;

}

System.out.println(s);

}

}

ex::

i/p: 500

o/p: 1F4