Hex to binary: two solutions in Matlab 

The  binary system (base 2) has only two symbols, '0' and '1'.

The following table shows the meaning of all the symbols in the hexadecimal  numbering system and their conversion to decimal or binary equivalents.

To convert a value from hex to binary, you merely translate each hex symbol to the equivalent 4-bit binary group. For example, the hex number A5A5 translates into the binary 1010010110100101 equivalent. 

Solution 1. Conversion from hex to decimal, and then from decimal to binary

In Matlab, we can go from hexadecimal to decimal, and then, from decimal to binary. We can embed one instruction into the other, like this: 

bin_str = dec2bin(hex2dec(hex_str))

So, we can use this concept, like this:

hex_str = 'AF5'
bin_str = dec2bin(hex2dec(hex_str))

 
Matlab’s answer is: 

bin_str = 101011110101

Solution 2. Conversion using a Switch-Case structure

We can develop a function to translate the table shown before. Our proposed method uses a switch-case structure.

% Hex to binary conversion
function b = h2b(h)
switch h
    case {'0'}
        b = '0000';
    case {'1'}
        b = '0001';
    case {'2'}
        b = '0010';
    case {'3'}
        b = '0011';
    case {'4'}
        b = '0100';
    case {'5'}
        b = '0101';
    case {'6'}
        b = '0110';
    case {'7'}
        b = '0111';
    case {'8'}
        b = '1000';
    case {'9'}
        b = '1001';
    case {'A', 'a'}
        b = '1010';
    case {'B', 'b'}
        b = '1011';
    case {'C', 'c'}
        b = '1100';
    case {'D', 'd'}
        b = '1101';
    case {'E', 'e'}
        b = '1110';
    case {'F', 'f'}
        b = '1111';
end

Now, we have to call the function for every hex character in the string, to convert each to a 4-bit binary number. One possible solution to separate the hex characters into 4-bit groups is shown here:

hex_str = input('Enter hexadecimal number: ', 's');
n = length(hex_str); 

bin_str = '';
for h = 1 : n
    bin_str = [bin_str h2b(hex_str(h))];
end
bin_str 

Let’s try this routine. 

Enter hexadecimal number: af50
bin_str = 1010111101010000