Switch case and a Menu Command

I'm trying to create a code that calculates an output in one unit but displays the answer in six different unit (the answer is converted to different units). I have a menu command so that the user can choose from the six different units but I need a switch case as my logical structure. I'm completely lost on how to write the switch case (I'm very, very new to matlab, so forgive my ignorance).

choice = menu('Choose a unit','in','ft','yd','m','cm','mm');

R = input('Input a value for the radius:');

result = (pi*R^2);

switch choice

      case 'in'
          result = pi*R^2;

      case 'ft'
          result = result/12;

      case 'yd'
          result = result/36;

      case 'm'
          result = result * .0254;

      case 'cm'
          result = result * 2.54;

      case 'mm'
          result = result * 25.4;

end

This was my first attempt that failed miserably, so any help would be appreciated.

[Randy Souza]

I have restored the original text of this question.

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Answer 1

[Walter Roberson]

menu() returns the number of the item chosen. So instead of case 'in', use case 1, and instead of case 'ft' use case 2, and so on.

Answer 2

[R__S]

I am not 100% sure it this is what you were wanting, but I assumed you wanted to be able to enter one value in a specific unit and get out the values for all the other units. If that is what you wanted feel free to use this code as you please.

   clc, clear %clears the command window and variables
   Unit = menu('Choose a unit','in','ft','yd','m','cm','mm'); %pop up display

 R = input('Input a value for the radius:');
 clc%clears the command screen after imputing a radius value
switch Unit %switich is the command, unit is the vaiable that we want to use
      case 1 %given inches %case must be given as a number, starting with 1=first option, 2=second option, and so on

   in = pi*R.^2; %finds the area of a circle in inches
    ft = in*.00694444; %takes the area in inches and coverts it into feet
  yds = in*.000771605;%same idea as before
  m = in*.00064516;
  cm = in*6.4516;
  mm = in*645.16;

    fprintf('\nA circle with a %3.2f Inch radius has an area of %5.10f Inches squared\n',R,in) %displays the Radius in the origional units and the new units
    fprintf('A circle with a %3.2f Inch radius has an area of %5.10f Feet squared\n',R,ft)
    fprintf('A circle with a %3.2f Inch radius has an area of %5.10f Yards squared\n',R,yds)
    fprintf('A circle with a %3.2f Inch radius has an area of %5.10f Meters squared\n',R,m)
    fprintf('A circle with a %3.2f Inch radius has an area of %5.10f Centimeters squared\n',R,cm)
    fprintf('A circle with a %3.2f Inch radius has an area of %5.10f Millimeters squared\n',R,mm)

      case 2 %given feet

    ft = pi*(R.^2) ;
     in = ft*144;
    yds = ft*.111111;
  m = ft* 9;
   cm = ft* 64516;
   mm = ft*836127;

    fprintf('\nA circle with a %3.2f Foot radius has an area of %5.10f Inches squared\n',R,in)
    fprintf('A circle with a %3.2f Foot radius has an area of %5.10f Feet squared\n',R,ft)
    fprintf('A circle with a %3.2f Foot radius has an area of %5.10f Yards squared\n',R,yds)
    fprintf('A circle with a %3.2f Foot radius has an area of %5.10f Meters squared\n',R,m)
    fprintf('A circle with a %3.2f Foot radius has an area of %5.10f Centimeters squared\n',R,cm)
    fprintf('A circle with a %3.2f Foot radius has an area of %5.10f Millimeters squared\n',R,mm)

      case 3 %given yards

   yds = pi*R.^2;
   ft = yds*9;
  in = yds*1296;
  m = yds*.836127;
  cm = yds*8361.27;
  mm = yds*836127;

    fprintf('\nA circle with a %3.2f Yard radius has an area of %5.10f Inches squared\n',R,in)
    fprintf('A circle with a %3.2f Yard radius has an area of %5.10f Feet squared\n',R,ft)
    fprintf('A circle with a %3.2f Yard radius has an area of %5.10f Yards squared\n',R,yds)
    fprintf('A circle with a %3.2f Yard radius has an area of %5.10f Meters squared\n',R,m)
    fprintf('A circle with a %3.2f Yard radius has an area of %5.10f Centimeters squared\n',R,cm)
    fprintf('A circle with a %3.2f Yard radius has an area of %5.10f Millimeters squared\n',R,mm)

      case 4 %given meter

   m = pi*R.^2;
    ft = m*10.7639;
  yds = m*1.19599;
  in = m*1550;
     cm = m*10000;
   mm = m*1000000;

    fprintf('\nA circle with a %3.2f Meter radius has an area of %5.5f Inches squared\n',R,in)
    fprintf('A circle with a %3.2f Meter radius has an area of %5.5f Feet squared\n',R,ft)
    fprintf('A circle with a %3.2f Meter radius has an area of %5.5f Yards squared\n',R,yds)
    fprintf('A circle with a %3.2f Meter radius has an area of %5.5f Meters squared\n',R,m)
    fprintf('A circle with a %3.2f Meter radius has an area of %5.5f Centimeters squared\n',R,cm)
    fprintf('A circle with a %3.2f Meter radius has an area of %5.5f Millimeters squared\n',R,mm)

      case 5 %given centimeters

   cm = pi*R.^2;
    ft = cm*.00107639;
  yds = cm*.000119599;
  m = cm*1000;
    in = cm*.155;
   mm = cm*100;
    fprintf('\nA circle with a %3.2f Centimeter radius has an area of %5.10f Inches squared\n',R,in)
    fprintf('A circle with a %3.2f Centimeter radius has an area of %5.10f Feet squared\n',R,ft)
    fprintf('A circle with a %3.2f Centimeter radius has an area of %5.10f Yards squared\n',R,yds)
    fprintf('A circle with a %3.2f Centimeter radius has an area of %5.10f Meters squared\n',R,m)
    fprintf('A circle with a %3.2f Centimeter radius has an area of %5.10f Centimeters squared\n',R,cm)
    fprintf('A circle with a %3.2f Centimeter radius has an area of %5.10f Millimeters squared\n',R,mm)

    case 6 %given millimeters

      mm = pi*R.^2;
      ft = mm*.000010764;
      yds = mm*.000001196;
      m = mm*.000001;
      cm = mm*.01;
      in = mm*.00155;

fprintf('\nA circle with a %3.2f Millimeter radius has an area of %5.10f Inches squared\n',R,in)
fprintf('A circle with a %3.2f Millimeter radius has an area of %5.10f Feet squared\n',R,ft)
fprintf('A circle with a %3.2f Millimeter radius has an area of %5.10f Yards squared\n',R,yds)
fprintf('A circle with a %3.2f Millimeter radius has an area of %5.10f Meters squared\n',R,m)
fprintf('A circle with a %3.2f Millimeter radius has an area of %5.10f Centimeters squared\n',R,cm)
fprintf('A circle with a %3.2f Millimeter radius has an area of %5.10f Millimeters squared\n',R,mm)

    otherwise 
        disp('Something went wrong')
end