Converting decimal to binary and vise versa

Hello Matlab Community,

I have a problem. I want to create a function that converts the decimal POSITIVE number that the user gives(maximum number that the user can give is 255) to binary(8-bit accuracy for every number from 0 to 255) and also another function that takes a binary number (max: 11111111 = 255) and converts it to decimal. I'd like to use the ''for'' loop and not functions of matlab like ''dec2bin'' or ''bin2dec''.I've tried a lot but still something doesn't work.

Thanks in Advance

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Rik]

Is this homework? If so, you can find guidelines for posting homework on this forum here.

[James Tursa]

Please post what you have tried so far and then we can make suggestions.

[John Dimopoulos]

clear;clc;
IP(1) = input('Give the first number of IP address:');
IP(2) = input('Give the second number of IP address:');
IP(3) = input('Give the third number of IP address:');
IP(4) = input('Give the fourth number of IP address:');
IP = [IP(1),IP(2),IP(3),IP(4)];
dec_nr = IP;
i = 1;
q = floor(dec_nr/2);
r = rem(dec_nr,2);
bin(i) = num2str(r(i));
while 2 <= q
    dec_nr = q;
    i = i + 1;
    q = floor(dec_nr/2);
    r = rem(dec_nr,2);
    bin(i) = num2str(r);
end
bin(i + 1) = num2str(q);
bin = fliplr(bin)

[John Dimopoulos]

How can I convert the IP(1),IP(2),IP(3),IP(4) decimals to binaries using 'for' loop ? Maybe writing 'for j = 1:4' in line 7, 'dec_nr = IP(j)' in line 8 and 'end' in line 21 ? If I do this I get false results when I try 2-or-less-digit numbers (example:25).What can I do ?

Answer 1

[Roger Stafford]

I’ll assume that the form of the binary version is a row vector, B, of eight ones or zeros, and that the "decimal" number is a double precision floating point number, D, whose value is an integer ranging from 0 to 255.

From D to B:

B = zeros(1,8);
for k = 8:-1:1
  B(k) = mod(D,2);
  D = (D-B(k))/2;
end

From B to D:

D = sum(B.*(2.^(7:-1:0)));

[John Dimopoulos]

Very nice ! If I want to do the convertion in a vector of 1 line and 4 columns how to modify your code using the 'for' loop?