Wrong answer of xor operation

a=(dec2bin(13))

a=1101

b=(dec2bin(14))

b=1110

c=xor(a,b)

the answer i get is c= 0 0 0 0

which is wrong. how should i solve this problem ?

[Raza Ali]

the answer should be

c= 0011

Answer 1

[Image Analyst]

Try this:

% Subtract '0' to get numerical array.
a=(dec2bin(13))-'0'
b=(dec2bin(14))-'0'
% Two ways to do xor:
d1 = (a | b) & ~(a & b)
d2=xor(a,b)

[Raza Ali]

can u explain why subtraction of 0 is required?

[Sagar Damle]

You can try these also -

a=(dec2bin(13))

b=(dec2bin(14))

% Since 'EX-OR'ing is same as modulo-2 addition

d1 = rem(a+b,2)

d2 = mod(a+b,2)

For more information,read this.

There are many functions in MATLAB to convert base 10 to base 2 of a number –

1. dec2base()

2. dec2bin()

3. de2bi()

4. dec2binvec()

However,outputs of these are are not in same format. Run this code on your computer for understaning purpose. See help about these functions in MATLAB.

Note : '0' represents ASCII value of zero(0) which is 48. So,

ans2 = dec2base(4,2) - '0'

is same as

ans2 = dec2base(4,2) – 48

Play with these functions! ENJOY!

% Program -

temp1 = dec2base(4,2)

ans1 = str2num(dec2base(4,2))

ans2 = dec2base(4,2) - '0'

temp2 = dec2bin(4)

ans3 = dec2bin(4) - '0'

temp3 = de2bi(4)

temp4 = de2bi(4,'right-msb')

ans4 = de2bi(4,'left-msb')

temp5 = dec2binvec(4)

ans5 = seqreverse(dec2binvec(4))

whos

[Raza Ali]

can you refer me any book or other material related to bits manipulation. like the above

[Raza Ali]

Thankx man

[Image Analyst]

Raza, subtraction of '0' turns it from a character string into an array of individual numbers to that we can use xor like you want to.

Answer 2

[Azzi Abdelmalek]

a and b are char, there is a difference betwenn

xor('1','0')

and

xor(1,0)

[John D'Errico]

To be honest, it does seem that xor should have a test for improper (non-numeric/non-logical) input, returning an error here, or at least a warning.

[Raza Ali]

so what should i do to solve my above question?

[Azzi Abdelmalek]

Jhon, it seems that any character of a string is considered as true

str='I am true'
not(str)

This explains the result given by xor.

[Raza Ali]

thanks man

[John D'Errico]

Yes, I recognize that. And thus my point. Since it is impossible to return a meaningful result, and it is likely that users, especially novices, can have problems, then an error should result. There can be no case where returning an error can be a problem for backwards compatibility, since xor never has returned anything meaningful for character input.