java conversions programs

In this post we will learn some of basic java programs which converting Binary to Decimal,Binary to Octal,Decimal to Octal etc... These programs are for freshers and  students those are new to programming language. Let's see the following examples.

1. Java program to convert Binary to Decimal

import java.util.*;
public class BinToDec
{
public static void main(String args[])
{
String binstr;
int decNum;
System.out.print("Enter Binary String(0-1):");
binstr=new Scanner (System.in).nextLine();
decNum=bintodec(binstr);
if(decNum==-1)
{
System.out.print("invalid string");
}
else
{
System.out.print("Decimal Number:"+decNum);
}
}
public static int bintodec(String binaryString)
{
int dnum=0;
int i=0;
int n;
int len=binaryString.length();
while(i<len)
{
n=binaryString.charAt(i)-48;//covert char '0' or '1' into integer 0 or 1
/* check for 0 and 1*/
if(n!=0&&n!=1)
{
return -1;//invalid string
}
dnum=(dnum*2)+n;
i++;
}
return(dnum);
}
}
Output:
Enter binary String(0-1): 110011
Decimal number:51

2.Java Program to covert Binary to Octal

import java.util.*;
public class BinToOct
{
public static void main(String args[])
{
int binary;
int remainder;
int decimal=0;
int octal=0;
int i=1;
System.out.print("Enter Binary number");
binary=new Scanner (System.in).nextInt();
/*convert Binary to Decimal number first */
while(binary!=0){
remainder=binary%10;
decimal=decimal+(remainder*i);
binary=binary/10;
i=i*2;
}
/*now convert to Decimal to octal number */
i=1;
while(decimal!=0)
{
remainder=decimal%8;
octal=octal+(remainder*i);
decimal=decimal/8;
i=i*10;
System.out.print("Octal Number:"+octal);
}
}
output:
enter Binary number: 1010
Octal number : 12

 3 Java program to convert Binary to HexaDecimal

import java.util.*;
public class BinToHex
{
public static void main(String args[])
{
int[] hexadeci=new int[100];
int dec=0;
int binary;
int i=1;
int j;
int rem;
System.out.print("Enter a Binary number:");
binary=new Scanner(System.in).nextInt();
/*binary to decimal*/
while(binary>0)
{
rem=binary%2;
dec=dec+(rem*i);
binary=binary/10;
i=i*2;
}
/*now decimal to HexaDecimal*/
i=0;
while(dec!=0)
{
hexadeci[i]=dec%16;
dec=dec/16;
i++;
}
System.out.print("Hexadecimal value:");
for(j=i-1;j>=0;j--)
{
if(hexadeci[j]>9)
{
System.out.print((char)(hexadeci[j]+55));
}
else
{
System.out.print(hexadeci[j]);
}
}
}
}

4. Java Program to convert Decimal to Binary
import java.util.*;
public class DecToBin
{
public static void main(String args[])
{
int i=0;
int j;
int dNum;
int[]bArr=new int[20];
System.out.print("Enter Decimal no:");
dNum=new Scanner(System.in).nextInt();
if(dNum==0)
{
System.out.print("Binary String is 0");
System.exit(0);
}
while(dNum>0)
{
bArr[i]=dNum%2;
dNum=dNum/2;
i++;
}
System.out.print("Binary String is");
for(j=i-1;j>=0)j--)
{
System.out.print(bArr[j]);
}
}
}
Output:
Enter Decimal no: 55
Binary String is 110111

5. Java  Program to covert Decimal to Octal

import java.util.*:
public class DecToOct
{
public static void main(String args[])
{
int decimal;
int remainder;
int octal=0;
int i=1;
System.out.print("enter a decimal number");
decimal=new Scanner(System.in).nextInt();
while(decimal!=0)
{
remainder=decimal%8;
octal=octal+(remainder*i);
decimal=decimal/8;
i=i*10;
}
System.out.print("octal number:"+octal);
}
}
Output:
Enter a decimal number: 100
octal number:144

6. Java program to convert Octal to Binary

import java.util.*;
public class OctToBin
{
public static void main(String args[])
{
int i=0;
System.out.print("enter any octal number:");
String octalNumber=new Scanner(System.in).nextLine();
int len=octalNumber.length();
System.out.print("Binary value:");
for(i=0;i<len;i++)
{
switch(octalNumber.charAt(i))
{
case '0':
              System.out.print("000");
               break;
case '1':
            System.out.print("001");
            break;
case '2':
            System.out.print("010");
            break;
case '3':
             System.out.print("011");
             break;
case '4':
            System.out.print("100");
            break;
case '5':
            System.out.print("101");
            break;
case '6':
            System.out.print("101");
            break;
case '7':
            System.out.print("111");
            break;
default:
           System.out.print("\n Invalid octal digit"+octalNumber.charAt(i));
return;
}// end of switch
}//end of loop
}
}
Output:
Enter any octal number: 12
Binary value: 001010

7. Java Program to convert Octal to Decimal

import java.util.*;
public class OctToDec
{
public static void main(String args[])
{
int octNumber;
int deciNumber=0;
int remainder;
int i=1;
System.out.print("enter an octal number:");
octNumber=new Scanner(System.in).nextInt();
while(octNumber!=0)
{
remainder=octNumber%10;
deciNumber+=remainder*i;
octNumber/=10;
i=i*8;
}
System.out.print("Decimal Number:"+decinumber);
}
}
Output:
Enter any octal number:256
Decimal number: 174