dotTutorials dotTutorials - 4 months ago 11
C# Question

'Goto' is this bad?

After doing some reseach on how to break through a secondary loop

while (true) { // Main Loop
for (int I = 0; I < 15; I++) { // Secondary loop
// Do Something
break; // Break main loop?
}
}


most people recommended to call the 'goto' function

Looking as the following example:

while (true) { // Main Loop
for (int I = 0; I < 15; I++) { // Secondary Loop
// Do Something
goto ContinueOn; // Breaks the main loop
}
}
ContinueOn:


However; I have often heard that the 'goto' statement is bad practice. The picture below is perfectly illustrating my point:
Series found

So




  • How bad is the goto statement really, and why?

  • Is there a more effective way to break the main loop than using the 'goto' statement?


Answer

EDIT:

How bad is the goto statement really, and why?

It depends on the exact situation. I can't remember any time where I found it made the code more readable than refactoring. It also depends on your personal view of readability - some people dislike it more than others, as is clear from the other answers. (As a point of interest, it's widely used in generated code - all of the async/await code in C# 5 is based on effectively a lot of gotos).

The problem is that situations where goto tends to be used tend to be the kind of situations where refactoring aids things anyway - whereas goto sticks with a solution which becomes harder to follow as the code gets more complicated.

Is there a more effective way to break the main loop than using the 'goto' statement?

Absolutely. Extract your method out into a separate function:

while (ProcessValues(...))
{
    // Body left deliberately empty
}

...

private bool ProcessValues()
{
   for (int i = 0; i < 15; i++)
   {
       // Do something
       return false;
   }
   return true;
}

I generally prefer doing this over introducing an extra local variable to keep track of "have I finished" - although that will work to, of course.

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