An equivalent to jump/goto ?

Hello all,

I would like to jump between my loops whole/for. I know that I can use the command break, but it doesn't work in this situation.

There is the architecture of my code :

    while (condition1)
        Action1
        while (Condition2)
            Action2
            for i=1:N
                if (Condition3)
                    Action3
                    %Goto second While loop
                elseif (Condition4)
                    Action4
                    %Goto first While loop
               end
           end
       end
   end

Is it possible to do these 'Goto' with Matlab ? or an equivalent ?

Thanks.

[Matt Fig]

Speak of the devil!

[Walter Roberson]

Mauro Alejandro Pereira comments to Loginatorist:

This is not a solution.

[Walter Roberson]

Mauro Alejandro Pereira:

Notice that Loginatorist's remark was posted as a Comment, not as an Answer. Individual Comments are for discussion, and need not be solutions.

Answer 1

[Sean de Wolski]

The MATLAB equivalent is to use functions that you call when you want to go somewhere else.

This is explained in the documentation for function, available here:

doc function

Answer 2

[Jan]

Only a small change solves the problem:

while (condition1)
  Action1
  Proceed = true;
  while (Condition2 && Proceed)
    Action2
    for i=1:N
      if (Condition3)
        Action3
        %Goto second While loop
        break;            % <== 
      elseif (Condition4)
        Action4
        %Goto first While loop
        Proceed = false;  % <==
        break;            % <==
      end
    end
  end
end

This is very similar to Matt Fig's solution, only the test of his bf is embedded in the condition of the WHILE.

[Matt Fig]

Yep. I use this similar construct too. Which one I choose depends on what I am doing. When translating old FORTRAN code, or when I am working with a FORTRAN programmer, (both occur frequently in my line of work) I am more likely to use my approach. When writing from scratch I am likely to use the one Jan shows.

Answer 3

[Matt Fig]

There has been a feature request for quite some time to allow BREAK to have a level passed to it. Perhaps add your name to the chorus of voices requesting such a feature. Until then, use this kind of thing....

cnt1 = 1;
cnt2 = 1;

while cnt1<10
    disp('In first loop')
    bf = 0; % Break flag for throwing back to first loop
    cnt1 = cnt1 + 1;
    while cnt2<10
        disp('In second loop')
        cnt2 = cnt2 + 1;
        for i=1:20
            if cnt2<5
                cnt2 = cnt2 + 1;
                disp('breaking back to 2nd loop')
                break
                %Goto second While loop
            elseif cnt1<5
                disp('breaking back to 1st loop')
                cnt1 = cnt1 + 1;
                bf = 1;   % set flag to go to first loop
                break
            end
        end

          if bf  % break out of second loop when set
              break
          end
      end
  end

Answer 4

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/26949-matlab-goto-statement

[Jan]

As usual I cannot hesitate to publish my hopes, that Matlab will get a COMEFROM in the future also.

[Walter Roberson]

As long as it isn't ALTER! Single worst programming feature I've ever seen!