Usage of "goto" - what's your opinion?

[nelson1mx]

Hello,

I've been dealing with a program for some hours and I finally solved it :), but I had to draw upon the "goto" sentence. I don't see any other way to modify the program since when it reaches certain condition I have to execute a some code above the current line.

My question is: what do you think about the usage of "goto"? does this exhibits poor programming abilities? Is it recommended to avoid "goto" sentence?

Cheers!

[Mats]

Can we see the program? I've never yet needed to use a goto.

[nelson1mx]

@Mats: Sure. It is a DFS for a Graph:

void DFS(int s)
{
	bool* isVisited=new bool[V];
	for (int x=0;x<V;x++)
	{
		isVisited[x]=false;
	}
	
	list<int> stack;

	stack.push_back(s);
	isVisited[s]=true;
	cout<<s<<" ";
	
	list<int>::iterator i;
	
start:
	while (stack.empty()==false)
	{
		i=adj[stack.back()].begin();
		while(isVisited[*i]==true)
		{
			i++;
			if(i==adj[stack.back()].end())
			{
				stack.pop_back();
				goto start;
			}
		}
		isVisited[*i]=true;
		stack.push_back(*i);
		cout<<*i<<" ";
	}
}

[Mats]

Perhaps the first reasonable use of goto I have ever seen on this forum!

[firedraco]

I would probably just use recursion here instead of emulating it with a stack/gotos.

[o1vk4iN6]

I believe one of the things to avoid is goto's going back up as that's where infinite loops are created.

Could do something like this instead:

	while (stack.empty()==false)
	{
                auto size = stack.size();

		i=adj[stack.back()].begin();
		while(isVisited[*i]==true)
		{
			i++;
			if(i==adj[stack.back()].end())
			{
				stack.pop_back();
				break;
			}
		}

                if(size == stack.size())
                {
			isVisited[*i]=true;
		 	stack.push_back(*i);
			cout<<*i<<" ";
                }
	}

[nelson1mx]

@All: Thanks for your comments! Based on them, I believe "goto" usage depends on the situation. In this case it may apply, but just as @firedraco suggests, it may be better to use recursion. It would be more elegant as well :P

I'm going to try the recursive alternative and I will post it once it works.

Cheers!

[Dy7SLyTq]

One is when ur using switches inside of loops

[S6k9GNh0]

goto statements are often used in parser generators for some reason. There has to be some validity to it.

[thebeto1of]

I remember working with someone who spent days trying to refactor code to get rid a single goto statement. There was absolutely no benefit to spending effort to refactor all the code, other than perceived aesthetics.