B-field of a Long Wire

%% B-field of a Long Wire
% Calculates the magnitude of the B-field at point p.

% Constants
muNaught = (4*pi)*10^-7                   %[T*m/A] Vacuum Permeability

% Inputs and Variables
I = input('What is the current creating the field in Amps?\n');
a = input('Coordinates or just radius?\n');
switch a
    case 1
        R = input('Input the distance from point p to the wire in coordinate form in brackets [x,y]\n');
        r = sqrt(R(1)^2+R(2)^2);
    case 2
        r = input('What is the radius in meters?\n');
end

% Outputs and Equations
B = muNaught*I/(2*pi*r);
fprintf('The magnitude is %.3e T',B)

if a == 1
    b = input('Would you like to calculate the x and y coordinates of the magnetic field? Y/N', 's');
    if b == 'Y'
        Bx = R(2)*B/r;
        By = R(1)*B/r;
        fprintf('The x and y coordinates are %.3e and %.3e', Bx, By)
    end
elseif a == 2
    theta = input('What is angle to calculate the x and y coordinates?\n');
    if theta == 0
    else
        Bx = sind(theta)*B/r;
        By = cosd(theta)*B/r;
        fprintf('The x and y coordinates are %.3e and %.3e', Bx, By)
    end
end

%{
**IMPORTANT**
    This code works under the assumption that the direction of the magnetic
    field is downwards. If the direction of the magnetic field is upwards
    then the calculation of the x and y coordinates will be reversed. You
    could easily implement a selection structure that gives users the
    option to choose which direction the of the arrow but I will not be
    making this edit anytime soon
******

The Bx and By components are calculated by sin(theta) or cos(theta) * B.
    Where the sin(theta) or cos(theta) is replaced with it's distance
    equivalent x-coordinate or y-coordinate / r
The user has the option to input the radius directly or use a coordinate
    system if the user chooses to input a coordinate system they will be given
    the option to calculate the x and y coordinates. If the user chooses to
    input the radius directly they will have to input the degrees to
    calculate the x and y coordinates
If the user does not to want to calculate the x and y coordinates, when
    given the choice to input an angle the user should just type in '0' to
    cancel
There is a function file wireBfield that will give the mag, Bx, and By that
    you can find on my page.
%}