CODEWITHSUNDEEP
language-agnosticgoto
Rizias
Rizias

Reputation: 211

Alternatives of goto and jump commands

I am working on a language where there is not any goto,jump function. For example, Matlab. Can you please help me on how to avoid using it? Is there any simple trick solving my problem?

Upvotes: 0

Views: 2377

Answers (3)

alexsmail
alexsmail

Reputation: 5813

As @Andrey mention you can use if or if-else statement. In many cases loops like while, for is one-to-one replacements to the if-else and goto.

You should also consider to use break and continue statement as @Oli said above.

In some rare cases you can use exception (I don't know whether the Matlab supports it) in order to "go back". This is somewhat controversial, but maybe in your case it will fit.

redothat:
foobar()
...

And inside foobar() in some place you have 

if cond
   goto redothat;
end

you can do:

while(true){
 try {
   foobar();
   ...
   break;
 }
 catch(YourApplicationException e){
   //do nothing, continiue looping
 }  
}

And inside foobar() in some place you have 

if cond
  throw YourApplicationException();
end

Or you can do something like this:

you can do:

boolean isOk = false;   
while(! isOk){
 try {
   foobar();
   ...
   isOk=true;
 }
 catch(YourApplicationException e){
   //do nothing, continiue looping
 }  
}

Upvotes: 1

Oli
Oli

Reputation: 16045

You should consider using break and continue

Instead of:

for ...
   ...
   if ...
      goto nextstuff:
   end
end
nextstuff:

You can do:

for ...
   ...
   if ...
      break
   end
end

And as @andrey said, you can often replace goto by if-else

Instead of doing:

if cond
  goto label
end
...
foobar()
...
label:
foobar2()

you can do:

if ~cond
  ...
  foobar()
  ...
end
foobar2()

When you use a goto to go back, you can replace it by a while:

Instead of doing:

redothat:
foobar()
...
if cond
   goto redothat;
end

you can do:

while cond
  foobar()
  ...
end

Upvotes: 3

Andrey Rubshtein
Andrey Rubshtein

Reputation: 20915

Well, first of all you might as well ask it without the tag, you might get better answers. That is because this kind of question is common to almost all of the modern languages.

Instead of goto and jump you should use either conditionals like if,if-else or loops like while,for, depending on what you want to achieve.

Check out GOTO still considered harmful?, Why is goto poor practise?.

Upvotes: 1

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