Jason arora - 1 year ago 89

Java Question

Given:A binary number in the form of String.Convert this into its 2's complement form

Example:

Input:

00000101

Output:

11111011

I know how to convert a binary number into its 1's compliment form. But I am unable to convert into 2 complement form.

For Example:

GivenString :111

1s Compliment 000

How to code1: Adding '1' to the 1's complement and 1+1=1?

MyCodeFor 1s Compliment:

`public static String complimentDecimal(String strnew)`

{

//Replace the 0s with 1s and 1s with 0s

StringBuilder sb = new StringBuilder();

for(int j=0;j<strnew.length();j++)

{

if(strnew.charAt(j)=='0')

sb.append("1");

else if(strnew.charAt(j)=='1')

sb.append("0");

}

String s1 = sb.toString();

}

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Answer Source

Convert the one's compliment to decimal form using `Integer.parseInt(<String value>, 2)`

You will get decimal form of the binary number. Add one to it and convert the number back to binary.

```
public static String complimentDecimal(String strnew)
{
int s2=Integer.parseInt(strnew,2);
if (s2==0)
{
String s4="1";
for(int j=0;j<strnew.length();j++)
{
s4+="0";
}
return s4;
}
else{
StringBuilder sb = new StringBuilder();
for(int j=0;j<strnew.length();j++)
{
if(strnew.charAt(j)=='0')
sb.append("1");
else if(strnew.charAt(j)=='1')
sb.append("0");
}
String s1 = sb.toString();
int s = Integer.parseInt(s1, 2);//parse int radix = 2 for binary
s++; //increment by one
return Integer.toBinaryString(s);
}
}
```

This will work for zero's.

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