I am getting error variable Accnew and ACCold does not exist in apex trigger

Question

1. trigger PractiseM on Account (before update) {
2. if (trigger.isBefore && trigger.isUpdate) {

3.    for(Account accNew : trigger.new)
   

4.        Account Accold = trigger.oldmap.get(Accnew.Id);
   

5.    If (accNew.Name != AccOld.name) {
   

6.        accNew.addError ('Please do not change the account name');
   

7.    }
   

8. } 9.}

Answer 1

You need curly braces. Your for loop in line 3 doesn't have braces so the scope is just line 4 and then you're out of the loop. So line 5 "thinks" you try to use undeclared variables.

Fix the braces and - since your indentation was lying to you - consider using something like Prettier / eslint for code formatting checks?