BinaryToDecimal

[rajeev]

package com.necre.oops5;

import java.util.Scanner;

public class BinaryToDecimal {
	
	public static void main(String[] args) {
	
		Scanner scanner=new Scanner(System.in);
		System.out.println("enter a binary no:");
	    String no=scanner.next();
		
		convert(no);
	}

	public static void convert(String no) {
		
		int decimalNo=0;
		int temp=1;
		int range=no.length()-1;
		
		for (int index = range; index >= 0; index--) {
			
			if (index==range) {
				decimalNo=no.charAt(index)*2*temp;
				System.out.println(no.charAt(index)+"*"+2+"*"+temp+":"+decimalNo);
			}
			else {
				decimalNo=decimalNo+no.charAt(index)*2*temp;
				System.out.println(no.charAt(index)+"*"+2+"*"+temp+":"+decimalNo);
				temp=temp*2;
			}
		}
		System.out.println("decimal no:"+decimalNo);
	}
	
}

I want to convert binary no to decimal no ........but i did some mistake which is giving some wrong output ...........where is that mistake...

output:

enter a binary no:
1010
0*2*1:96
1*2*1:194
0*2*2:386
1*2*4:778
decimal no:778

[Junky]

I didn't look at your code but from the output it seems you are misunderstanding how the conversion works.
Below ^ means "raised to the power of"
1010 = (1*2^3) + (0*2^2) + (1*2^1) + (0*2^0)
= (1*8) + (0*4) + (1*2) + (0*1) // remember that anything raised to the power of 0 is 1.
= 8 + 0 + 2 + 0
= 10

You need to rethink your algorithm. You should be able to do this with a single loop.

[Junky]

Now I have looked at the code. Apart from getting the power wrong and not doing any addition. You are also multiplying the char (its ascii value) and not its numeric value

[allaudin]

You can also use

Integer.toBinaryString(intValue)

[Junky]

OP is trying the opposite conversion: binary to integer. Besides I assume this is an assignment where they must write the code themselves.

[rajeev]

How can I avoid multiplying by ascii value ............... any converson require?????????modify my code .......

[Junky]

Look at the Character class. It has a method that can convert '1' to 1.

[rajeev]

In Character class getNumeric() method is there ............ but i used String instead of Character class.

[Junky]

As long as it works!