Which code you suggest?
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What if you have two nested loops? It's a lot harder to exit them both...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
Quote:
What if you have two nested loops?
You can't get out of the matrix. :) I didn't say there was never a reason for returning from multiple places. I just said I prefer not to.
There are only 10 types of people in the world, those who understand binary and those who don't.
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Quote:
What if you have two nested loops?
You can't get out of the matrix. :) I didn't say there was never a reason for returning from multiple places. I just said I prefer not to.
There are only 10 types of people in the world, those who understand binary and those who don't.
Trust me, I took the red pill a loooong time ago!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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I'm a fan of early exit, so I'd go with the first one (assuming that's what this post is about). It doesn't really matter much in smaller routines like the one above, but when you have longer ones it can be difficult to follow retValue around the function to find out where you are really setting the return value. The first method is shorter because you can run a case through in your head without having to write down variables. I think the question boils down to Early Exit versus Single Exit. There's a lot of debate on the merits of both so I think your answers are going to be somewhat distributed between them. I've yet to hear a debate for single exit that I agree with over the merits of early exit...
Quote:
it can be difficult to follow retValue around the function to find out where you are really setting the return value.
That's funny. That's the same reason people usually argue for single exit, in that it is hard to figure out why some code isn't running because it turns out there was a return statement earlier that you hadn't noticed. :) To each his own.
There are only 10 types of people in the world, those who understand binary and those who don't.
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Trust me, I took the red pill a loooong time ago!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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But you're missing the fact that you can exit a loop when you find what you need. You don't have to continue processing.
There are only 10 types of people in the world, those who understand binary and those who don't.
the 2 loops are a good example, but for me is easier to track multiple exit points than it is to track changes on a variable. there may be a hundred variables involved, the return value can get reset, millions of things can happen, but when there's a return statement, i know it's over. whatever i've at that point is the result, i can track individual cases one at a time. for me it's really easier to track execution paths this way, is it different for you? the ammount of different opnions when we talk about code is just funny ;P opnions are the oposite of highlanders, there can never be only one.
I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
First of all, the second code should have a 'break' as follows. Otherwise, it just continues to loop pointlessly, even if it find "ABC" in the first item.
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
{
if (s == "ABC")
{
retValue=true;
break;
}
}
return retValue;
}Personally, I choose the this method over your first method, since it has a single point of return to the method. About the performance, both versions should be identical as this method would only execute 2 steps extra.
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
So, this is certainly choosing between the lesser of 2 evils :wtf: If I HAD to choose one of both, the first example would be it, even if only for performance reasons - since the loop breaks when ABC was found. But having said that... No. Just... No. :-D
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The first will be faster, as it will exit as soon as finding "ABC" Alternatively,
return values.Contains("ABC")
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
Code 1 would be my preference as it is the default indentation model for Visual Studio. I don't see the point of re-setting the default model or turning off the auto-complete for the sake of a preference; I find that the usual combination of indents provides a readable and fast coding format which is pretty good at revealing errors and incomplete blocks due to items not aligning conventionally. In other words, you can pick up errors in peripheral vision, which is quick.
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What if you have two nested loops? It's a lot harder to exit them both...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
No. Actually it isn't. All you have to do (hush my mouth) is add a label to your single return point at the bottom of your procedure, and then (and I can't believe I'm saying this in open forum) "goto" that label. Simples! Yes - I am more than old enough to know better but I do still use goto from time to time and I'm not totally averse to the odd setjmp/longjmp pair in my code. ;P
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
I would go with #1. Number 2 should have a break statement and would work too.
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
{
retValue=true;
break;
}
return retValue;
}The signature is in building process.. Please wait...
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No. Actually it isn't. All you have to do (hush my mouth) is add a label to your single return point at the bottom of your procedure, and then (and I can't believe I'm saying this in open forum) "goto" that label. Simples! Yes - I am more than old enough to know better but I do still use goto from time to time and I'm not totally averse to the odd setjmp/longjmp pair in my code. ;P
Or use a return, which is cleaner, and a lot more obvious...and won't get you strung up by the "goto is evil" lynch mob. And in this case it would be a horrible and unnecessary use of goto which would probably be deserving of the hempen necktie!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Quote:
it can be difficult to follow retValue around the function to find out where you are really setting the return value.
That's funny. That's the same reason people usually argue for single exit, in that it is hard to figure out why some code isn't running because it turns out there was a return statement earlier that you hadn't noticed. :) To each his own.
There are only 10 types of people in the world, those who understand binary and those who don't.
I also go mostly for early exit. This helps to keep the code to the left as much as possible. Besides. if a method gets too long... you're doing it wrong ;)
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Or use a return, which is cleaner, and a lot more obvious...and won't get you strung up by the "goto is evil" lynch mob. And in this case it would be a horrible and unnecessary use of goto which would probably be deserving of the hempen necktie!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Interestingly, the only use MS recommends for
gotois exiting multiple loops.Yes, but MS recommends you install Windows 8 on your computer...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Yes, but MS recommends you install Windows 8 on your computer...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
Neither. IMHO the best approach for a non-trivial function is to use a single return value declared and initialized at the start, along with a flag indicating premature abortion. Then, over the whole length of your function, no matter how long it is, you can always add that flag to every loop or (top level) if statement to prevent unnecessary execution of code. In the example above, the return value can double as abortion flag: use it to prematurely break out of the loop to prevent unnecessary execution of code. Personally, for any function with more than about half a dozen of control statements, I introduce a boolean variable called 'done' or similar that I use to short-cut later control statements. This way I don't normally need to increase the nesting level by more than 1.
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What if you have two nested loops? It's a lot harder to exit them both...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
Easy: introduce a flag indicating when you're done processing (for whatever reason). You can either add that flag to the breaking condition of control statements, or add a single additional nesting layer inquiring the state of that flag everytime you're about to do some more processing (that could be skipped). I've been using that concept successfully for a long time in legacy applications that have lots of very long functions with very high nesting levels. This method at most adds one nesting level, if at all, and it helps keeping track of stuff I need to clean up at various nesting levels before actually exiting the function.
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Easy: introduce a flag indicating when you're done processing (for whatever reason). You can either add that flag to the breaking condition of control statements, or add a single additional nesting layer inquiring the state of that flag everytime you're about to do some more processing (that could be skipped). I've been using that concept successfully for a long time in legacy applications that have lots of very long functions with very high nesting levels. This method at most adds one nesting level, if at all, and it helps keeping track of stuff I need to clean up at various nesting levels before actually exiting the function.
Yes you can, but...a return is a lot, lot cleaner!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Code1:
Boolean DoSomething(string\[\] values) { foreach (string s in values) if (s == "ABC") return true; return false; }Code2:
Boolean DoSomething(string[] values)
{
bool retValue = false;
foreach (string s in values)
if (s == "ABC")
retValue=true;
return retValue;
}in the above 2 codes which code you will suggest and why? waiting for your valuable comments. Thanks --RA
It depends. There are times when it is necessary to exit as soon as a decision is reached, as I expect the performance of foreach to be O(n). For example, if a function is trying to find the first prime number within an array then you need to exit as soon as the condition is true, otherwise much time may be wasted. In the example given it depends how large I expect the string array to be, clearly the function itself can potentially take a string array of any size so method 1 seems preferable to me. However, if you don't like multiple return points then use 'break'. A more complex function is often clearer to read and debug if there is only one return point, and this is preferable if speed is not an issue. For example, if a function decides which way a bug is going to turn - left or right, then it may test many conditions, none of which may involve operations on large collections. In this example, it is probably preferable to have only a single return point.
