I am always in the habit of using if, else-if statement instead of multiple if statements.
Example:
int val = -1;
if (a == b1) {
return c1;
} else if (a == b2) {
return c2;
} ...
...
} else {
return c11;
}
How does it compare to example 2:
if (a == b1) {
return c1;
}
if (a == b2) {
return c2;
}
....
if (a == b11) {
return c11;
}
I know functionality wise they are the same. But is it best practice to do if else-if, or not? It's raised by one of my friends when I pointed out he could structure the code base differently to make it cleaner. It's already a habit for me for long but I have never asked why.
if-elseif-else statements stop doing comparisons as soon as it finds one that's true. if-if-if does every comparison. The first is more efficient.
Edit: It's been pointed out in comments that you do a return within each if block. In these cases, or in cases where control will leave the method (exceptions), there is no difference between doing multiple if statements and doing if-elseif-else statements.
However, it's best practice to use if-elseif-else anyhow. Suppose you change your code such that you don't do a return in every if block. Then, to remain efficient, you'd also have to change to an if-elseif-else idiom. Having it be if-elseif-else from the beginning saves you edits in the future, and is clearer to people reading your code (witness the misinterpretation I just gave you by doing a skim-over of your code!).
What about the case where b1 == b2? (And if a == b1 and a == b2?)
When that happens, generally speaking, the following two chunks of code will very likely have different behavior:
if (a == b1) {
/* do stuff here, and break out of the test */
}
else if (a == b2) {
/* this block is never reached */
}
and:
if (a == b1) {
/* do stuff here */
}
if (a == b2) {
/* do this stuff, as well */
}
If you want to clearly delineate functionality for the different cases, use if-else or switch-case to make one test.
If you want different functionality for multiple cases, then use multiple if blocks as separate tests.
It's not a question of "best practices" so much as defining whether you have one test or multiple tests.
The are NOT functionally equivalent.
The only way it would be functionally equivalent is if you did an "if" statement for every single possible value of a (ie: every possibly int value, as defined in limits.h in C; using INT_MIN and INT_MAX, or equivalent in Java).
The else statement allows you to cover every possible remaining value without having to write millions of "if" statements.
Also, it's better coding practice to use if...else if...else, just like how in a switch/case statement, your compiler will nag you with a warning if you don't provide a "default" case statement. This prevents you from overlooking invalid values in your program. eg:
double square_root(double x) {
if(x > 0.0f) {
return sqrt(x);
} else if(x == 0.0f) {
return x;
} else {
printf("INVALID VALUE: x must be greater than zero");
return 0.0f;
}
}
Do you want to type millions of if statements for each possible value of x in this case? Doubt it :)
Cheers!
This totally depends on the condition you're testing. In your example it will make no difference eventually but as best practice, if you want ONE of the conditions to be eventually executed then you better use if else
if (x > 1) {
System.out.println("Hello!");
}else if (x < 1) {
System.out.println("Bye!");
}
Also note that if the first condition is TRUE the second will NOT be checked at all but if you use
if (x > 1) {
System.out.println("Hello!");
}
if (x < 1) {
System.out.println("Bye!");
}
The second condition will be checked even if the first condition is TRUE. This might be resolved by the optimizer eventually but as far as I know it behaves that way. Also the first one is the one is meant to be written and behaves like this so it is always the best choice for me unless the logic requires otherwise.
if and else if is different to two consecutive if statements. In the first, when the CPU takes the first if branch the else if won't be checked. In the two consecutive if statements, even if the the first if is checked and taken, the next if will also be check and take if the the condition is true.
I tend to think that using else if is easier more robust in the face of code changes. If someone were to adjust the control flow of the function and replaces a return with side-effect or a function call with a try-catch the else-if would fail hard if all conditions are truly exclusive. It really depends to much on the exact code you are working with to make a general judgment and you need to consider the possible trade-offs with brevity.
With return statements in each if branch.
In your code, you have return statements in each of the if conditions. When you have a situation like this, there are two ways to write this. The first is how you've written it in Example 1:
if (a == b1) {
return c1;
} else if (a == b2) {
return c2;
} else {
return c11;
}
The other is as follows:
if (a == b1) {
return c1;
}
if (a == b2) {
return c2;
}
return c11; // no if or else around this return statement
These two ways of writing your code are identical.
The way you wrote your code in example 2 wouldn't compile in C++ or Java (and would be undefined behavior in C), because the compiler doesn't know that you've covered all possible values of a so it thinks there's a code path through the function that can get you to the end of the function without returning a return value.
if (a == b1) {
return c1;
}
if (a == b2) {
return c2;
}
...
if (a == b11) {
return c11;
}
// what if you set a to some value c12?
Without return statements in each if branch.
Without return statements in each if branch, your code would be functionally identical only if the following statements are true:
You don't mutate the value of a in any of the if branches.
== is an equivalence relation (in the mathematical sense) and none of the b1 thru b11 are in the same equivalence class.
== doesn't have any side effects.
To clarify further about point #2 (and also point #3):
== is always an equivalence relation in C or Java and never has side effects.
In languages that let you override the == operator, such as C++, Ruby, or Scala, the overridden == operator may not be an equivalence relation, and it may have side effects. We certainly hope that whoever overrides the == operator was sane enough to write an equivalence relation that doesn't have side effects, but there's no guarantee.
In JavaScript and certain other programming languages with loose type conversion rules, there are cases built into the language where == is not transitive, or not symmetric. (In Javascript, === is an equivalence relation.)
In terms of performance, example #1 is guaranteed not to perform any comparisons after the one that matches. It may be possible for the compiler to optimize #2 to skip the extra comparisons, but it's unlikely. In the following example, it probably can't, and if the strings are long, the extra comparisons aren't cheap.
if (strcmp(str, "b1") == 0) {
...
}
if (strcmp(str, "b2") == 0) {
...
}
if (strcmp(str, "b3") == 0) {
...
}
I prefer if/else structures, because it's much easier to evaluate all possible states of your problem in every variation together with switches. It's more robust I find and quicker to debug especially when you do multiple Boolean evaluations in a weak-typed environment such as PHP, example why elseif is bad (exaggerated for demonstration):
if(a && (c == d))
{
} elseif ( b && (!d || a))
{
} elseif ( d == a && ( b^2 > c))
{
} else {
}
This problem has beyond 4^2=16 boolean states, which is simply to demonstrate the weak-typing effects that makes things even worse. It isn't so hard to imagine a three state variable, three variable problem involved in a if ab elseif bc type of way.
Leave optimization to the compiler.
In most cases, using if-elseif-else and switch statements over if-if-if statements is more efficient (since it makes it easier for the compiler to create jump/lookup tables) and better practice since it makes your code more readable, plus the compiler makes sure you include a default case in the switch. This answer, along with this table comparing the three different statements was synthesized using other answer posts on this page as well as those of a similar SO question.
I think these code snippets are equivalent for the simple reason that you have many return statements. If you had a single return statements, you would be using else constructs that here are unnecessary.
Your comparison relies on the fact that the body of the if statements return control from the method. Otherwise, the functionality would be different.
In this case, they perform the same functionality. The latter is much easier to read and understand in my opinion and would be my choice as which to use.
They potentially do different things.
If a is equal to b1 and b2, you enter two if blocks. In the first example, you only ever enter one. I imagine the first example is faster as the compiler probably does have to check each condition sequentially as certain comparison rules may apply to the object. It may be able to optimise them out... but if you only want one to be entered, the first approach is more obvious, less likely to lead to developer mistake or inefficient code, so I'd definitely recommend that.
CanSpice's answer is correct. An additional consideration for performance is to find out which conditional occurs most often. For example, if a==b1 only occurs 1% of the time, then you get better performance by checking the other case first.
Gir Loves Tacos answer is also good. Best practice is to ensure you have all cases covered.
Related
I am refactoring a function with too many if-else's, something like the following but more complicated. Some major characteristics of this function are:
It bails out early for many pre-conditions (e.g., condition1() and condition2()).
It only does some meaningful stuff on very specific scenarios (e.g., doA() and doB()). (Oh yeah, the beauty of temporary bug fixing!)
Some pre-conditions may or may not be independent of additional conditions (e.g., condition3/4/5/6()).
retT foo() { // total complexity count = 6
if (!condition1()) { // complexity +1
return retT{};
}
if (!condition2()) { // complexity +1
return retT{};
}
if (condition3()) { // complexity +1
if (condition4() || condition5()) { // complexity +2
return doA();
}
else if (condition6()) { // complexity +1
return doB();
}
}
return retT{};
}
The goal is to call out those actual works on their precise conditions rather than leaving them vulnerable to the change of the if-else structure in foo(). More specifically, I would like to turn foo() into something like this:
retT foo() { // total complexity count = 4
ConditionalCommand<retT> conditionalDoA{doA};
conditionalDoA.addCondition(condition1());
conditionalDoA.addCondition(condition2());
conditionalDoA.addCondition(condition3());
conditionalDoA.addCondition(condition4() || condition5()); // complexity +1
ConditionalCommand<retT> conditionalDoB{doB};
conditionalDoB.addCondition(condition1());
conditionalDoB.addCondition(condition2());
conditionalDoB.addCondition(condition3());
conditionalDoB.addCondition(!(condition4() || condition5())); // complexity +2
conditionalDoB.addCondition(condition6());
for (auto& do : {conditionalDoA, conditionalDoB}) {
if (do()) { // complexity +1
return do.result();
}
}
return retT{};
}
This makes the implementation more linear and the conditions for performing a particular work more explicit. I understand that it would be equivalent to just creating a first-level if-clause for each work with all the added conditions listed, but the above code would:
reduce our internal complexity measurement (if-else, logical operators, and ternary based, as illustrated in the code comments),
prevent future intrusion into the first-level if-clauses by a new developer, for example, who wants to doC() instead of doA() if condition7() is true, and
allow me to refine each work's conditions independently of those of the other works (recall that some conditions might be depending on each other).
So the question is, is there any existing std or boost utility that does what ConditionalCommand does so I don't need to reinvent the wheel?
Edit: conclusion at the top, frame challenge below.
Back to the original question, is there anything existing in std or boost to do what ConditionalCommand does?
OK, if you're really not worried about the fact that this design violates your own stated requirements, the answer is: NO. Nothing does exactly this.
However, you could just write something like
std::array condA { condition1(), condition2(), condition3(),
(condition4() || condition5()) };
if (std::ranges::all_of(condA, std::identity{})) doA();
if (std::ranges::all_of(
std::initializer_list<bool>{
condition1(), condition2(), condition3(),
(condition4() || condition5()),
condition6()
},
std::identity{})
)
doB();
or whatever takes your fancy. You're only suggesting a very thin convenience layer over this logic.
This makes the implementation more linear
Between perfectly linear control flow and a perfectly linear data structure, I don't really see any advantage either way on this criterion.
the conditions for performing a particular work more explicit
If by "more explicit" you mean "more declarative", then I guess so. You've hidden everything that is actually going on inside some mystery templates though, so it had better be very clear, intuitive and well documented.
reduce our internal complexity measurement (if-else, logical operators, and ternary based, as illustrated in the code comments),
Your "internal complexity measurement" is, frankly, stupid. If you optimize for a bad objective, you'll get a bad result.
Here you have very obviously increased overall complexity, increasing the learning curve for new developers, making the relationship between conditions and their consequences less clear and control flow much harder to debug.
But you've done it in a way that your "internal complexity measurement" chooses to ignore, so it looks like an improvement.
Although I dislike cyclomatic complexity as a broad measure, if yours is genuinely so much higher than shown in the question that refactoring is required - I'd still try just refactoring the procedural code before I considered your proposal.
prevent future intrusion into the first-level if-clauses by a new developer, for example, who wants to doC() instead of doA() if condition7() is true
Just write unit tests for every combination of your 7 conditions (or a single test that runs every permutation) and let your junior developer find out for themselves when the CI server complains about their branch.
You're not helping them get less junior by obfuscating your code like this, you're trying to insulate yourself from their mistakes in a way that doesn't actually help them improve.
Also, the original control flow may even have bugs in them
In that case you should definitely be writing test cases first! You're talking about refactoring code you don't trust in a way that violates your own stated requirements with no way to validate the result.
allow me to refine each work's conditions independently of those of the other works (recall that some conditions might be depending on each other).
If you really want a less error-prone way of organizing this, these condition inter-dependencies should be encoded explicitly. At the moment you can still break everything by adding conditions in the wrong order.
Further, you're currently executing all conditions unconditionally except for the short-circuit evaluation of conditions 4 & 5. Is this even well-defined? Is it guaranteed to remain well-defined?
Still further, you're now evaluating each condition multiple times, once for each possible action.
If you really must encode this in data rather than code, it could be something like an explicit dependency graph (so condition2 depends-on condition1 and is never executed unless that dependency evaluates to true). Then you can have multiple leaf actions attached to the same graph, and don't need any redundant re-evaluations.
To be fair, implementing this is a pain, but at least it satisfies your dependency requirement.
I agree with all the others that your attempt is just hiding complexity under a questionably more readable blanked. I find it much more unreadable than the original.
I think your only hope is to look at the original code and play untangle with it.
In your simplified example you have more return statements than possible returned values, and I bet in the original too, you have far more returns than possible returned values. So why don't you simply make a map (with pen and paper) of what condition leads to what return value?
Taking your simple example,
retT{} is returned only if !c1 || !c2 || !c3 || (!c4 && !c5 && !c6)
doA() is returned only if c1 && c2 && c3 && (c4 || c5)
doB() is returned only if c1 && c2 && c3 && c6
Notice that the first boolean can be re-written, using De Morgan laws, like !(c1 && c2 && c3 && (c4 || c5 || c6)).
Follows the observation that the only important booleans are actually these:
bool b1 = c1 && c2 && c3;
bool b2 = c4 || c5;
bool b3 = c6;
You can then rewrite your logic as
doA() is returned only if b1 && b2, call it p1
doB() is returned only if b1 && b3, call it p2
retT{} is returned only if !(b1 && (b2 || b3)) = !((b1 && b2) || !(b1 && b3)) = !(b1 && b2) && !(b1 && b3) = !p1 && !p2
the last sequence of equalities is the verification that all branches indeed lead to a return (otherwise the code would be erroneous).
With the above in mind (and on paper) the code can be simplified like this:
bool b1 = c1 && c2 && c3;
bool b2 = c4 || c5;
bool b3 = c6;
if (b1) {
if (b2) {
return doA();
}
if (b3) {
return doB();
}
}
return retT{};
or, if you are really scared about the time needed to compute the booleans, you can compute than "lazily":
bool b1 = c1 && c2 && c3;
if (b1) {
bool b2 = c4 || c5;
if (b2) {
return doA();
}
//bool b3 = c6;
if (/*b3*/c6) {
return doB();
}
}
return retT{};
I come across a lot of logic work where I'm not sure what design pattern is better for if statements. In these situations, I can usually put in a nested if statement, or alternatively. These two cases are shown below. What are the pros and cons of both, is there a standard I should follow?
if (val > 0 && is_on)
{
// (1)
}
else if (val > 0)
{
// (2)
}
else
{
// (3)
}
if (val > 0)
{
if(is_on)
{
// same as (1)
}
else
{
// same as (2)
}
}
else
{
// same as (3)
}
I don't think there is any specific pros or cons to any of the approach. Its all depends upon how you want to design your code and what you think is more readable to anyone who is looking at your code for the first time.
As per me, the first approach looks better as its more readable and contains fewer lines of code.
The first approach is more readable. But as the logic expressions (e.g. "val > 0 && is_on") get longer, it starts to make more sense to merge towards the second approach. The second one is easier to debug, so you could start there and then merge back. I'd match the style of the surrounding code/"code-policy" ultimately.
While the other answers are absolutely right in that your primary focus should be be readability, I want to address another difference: execution performance.
In the first example, there are 2 conditions that need evaluated before the else branch can run. If as we scale the number of conditions baked into this else/if ladder, the amount of evaluation to get to the else branch grows linearly. Now, we aren't expecting to have ten thousand conditions or anything, but it is something to take note of nonetheless.
Now, in your second example, we check the common condition between the first two branches, and if that fails, we quick-fail to the else branch, with no extra tests. In the extreme case, this can somewhat resemble a binary search for the correct code block- branching left and right until it finds its match, as opposed to a linear scan that checks each in order one-by-one.
Now, does this mean you should use the latter? Not necessarily- readability is more important, and if you're writing in a compiled language, the compiler will likely optimize away all that away anyways. And even if you're in an interpreted language, the performance hit is probably going to be negligible compared to everything else anyways, unless this is the hot section of a hot loop.
However, if you are bothered by the "wastefulness" of the repetition in the first example, but would rather avoid huge amounts of nesting, often languages will provide an assignment expression syntax, giving you a 3rd option, where you compute the result once and store it to a variable inline, for reuse in subsequent code.
For example:
if (expensive_func1() > 0 && is_on)
{
// (1)
}
else if (expensive_func1() > 0 && expensive_func2() > 0)
{
// (2)
}
else
{
// (3)
}
Becomes:
if ((is_alive = expensive_func1() > 0) && is_on)
{
// (1)
}
else if (is_alive && expensive_func2() > 0)
{
// (2)
}
else
{
// (3)
}
This saves us from recomputing the common sub expressions between our conditionals, in languages were we can't rely on a compiler to do that for us. Sure, we could just assign these to variables explicitly before the if statements, but then we bite the bullet of evaluating all shared expressions, rather than lazily evaluating them as needed (imagine we compute expensive_func2 > 0 for reuse in a 3rd if/else, only to find out we didn't need it, that we're taking the first branch).
Newbie here and I just want to know should I use ELSE IF for something like below:
(function)
IF x==1
IF x==2
IF x==3
That is the way I am using, because the x will not be anything else. However, I think that if the x is equal to 1, the program still gonna run through the following codes (which turn out to be FALSE FALSE FALSE ...). Should I use ELSE IF so it won't have to run the rest? Will that help the performance?
Why don't I want to use ELSE IF? because I'd like each code block (IF x==n) to be similar, not like this:
IF x==1
ELSE IF x==2
ELSE IF x==3
(each ELSE IF block is part of the block above it)
But the program will repeatedly call this function so I am worried about the performance or delay.
Short answer: If you do not need to handle a case where multiple conditions might be true at the same time, always use
if (condition) {
//do something
}
else if (other_condition) {
//do something else
}
else { //in all other conditions
//default behaviour
}
Long answer:
As others have already stated, performance is not really a big concern (unless you are writing production code for enterprise software targeted at colossal businesses). In case performance is indeed crucial though, you should go for the above format anyway. So that might be a good practice/habit to get used to (especially if you are now starting your code journey)
Switch could be an alternative, but since you haven't specified the language I would avoid suggesting it since, in some languages, it defaults to fall-through (which might get you where you started in the first place and confuse you even more)
Performance might not be a concern. But keep in mind that logic errors are a huge enemy to programming, and your solution is prone to them if you don't actually need it to be able to match more than one cases. Consider the following case.
if (x == 1) {
x = x + 1
}
if (x == 2) {
x = x + 2
}
if (x >= 3) {
print("Error: x should only be 1 or 2!")
}
In this case, you would expect that if x >= 3 you would warn about an error in value since you only had in mind handling the values 1 or 2. Actually though, even if the value of x is 1 or 2 (which you have considered to be valid) the same error message would be printed!. That's because you have allowed the possibility of more than one conditions being checked and the respective code block being executed each time. Note that this is an oversimplified example. In times, this can be a great pain! Especially if you collaborate with others and you share the code and you are aiming for expendable and maintainable code.
To conclude, do not use a simpler solution if you haven't thought it through. Go for the complete one instead and take in mind all possible outcomes (usually the worst case scenarios and even future features and code).
Best Regards!
If the value being tested is expected to be able to match multiple in a single calling, then test each (IF, IF, ...).
If the value is expected to only match one, then check for it and stop if you find it (IF, ELSE IF, ELSE IF...).
If the values are expected to be one of a known set, then go right to it (switch).
Assuming this is javascript, but this should be about the same for anything else.
The code inside the if statement will only be run if the condition you provide it is true. For example, if you declare x = 1, we could have something like:
function something() {
if(x == 1) {
//do this
}
if(x == 2) {
//do that
}
if(x == 3) {
//do this and that
}
The first block would be run and everything else is ignored. An else-if statement will run if the first if statement is false.
function something() {
if(x == 1) {
//do this
}
else if(x == 2) {
//do that
}
So if x == 1 was false, the next statement would be evaluated.
As for performance, the difference is way too little for you to care about. If you have many conditions you need to test, you may want to look into a switch statement.
I have a Heaviside step function centered on unity for any data type, which I've encoded using:
template <typename T>
int h1(const T& t){
if (t < 1){
return 0;
} else if (t >= 1){
return 1;
}
}
In code review, my reviewer told me that there is not an explicit return on all control paths. And the compiler does not warn me either. But I don't agree; the conditions are mutually exclusive. How do I deal with this?
It depends on how the template is used. For an int, you're fine.
But, if t is an IEEE754 floating point double type with a value set to NaN, neither t < 1 nor t >= 1 are true and so program control reaches the end of the if block! This causes the function to return without an explicit value; the behaviour of which is undefined.
(In a more general case, where T overloads the < and >= operators in such a way as to not cover all possibilities, program control will reach the end of the if block with no explicit return.)
The moral of the story here is to decide on which branch should be the default, and make that one the else case.
Just because code is correct, that doesn't mean it can't be better. Correct execution is the first step in quality, not the last.
if (t < 1) {
return 0;
} else if (t >= 1){
return 1;
}
The above is "correct" for any datatype of t than has sane behavior for < and >=. But this:
if (t < 1) {
return 0;
}
return 1;
Is easier to see by inspection that every case is covered, and avoids the second unneeded comparison altogether (that some compilers might not have optimized out). Code is not only read by compilers, but by humans, including you 10 years from now. Give the humans a break and write more simply for their understanding as well.
As noted, some special numbers can be both < and >=, so your reviewer is simply right.
The question is: what made you want to code it like this in the first place? Why do you even consider making life so hard for yourself and others (the people that need to maintain your code)? Just the fact that you are smart enough to deduce that < and >= should cover all cases doesn't mean that you have to make the code more complex than necessary. What goes for physics goes for code too: make things as simple as possible, but not simpler (I believe Einstein said this).
Think about it. What are you trying to achieve? Must be something like this: 'Return 0 if the input is less than 1, return 1 otherwise.' What you've done is add intelligence by saying ... oh but that means that I return 1 if t is greater or equal 1. This sort of needless 'x implies y' is requiring extra think work on behalf of the maintainer. If you think that is a good thing, I would advise to do a couple of years of code maintenance yourself.
If it were my review, I'd make another remark. If you use an 'if' statement, then you can basically do anything you want in all branches. But in this case, you do not do 'anything'. All you want to do is return 0 or 1 depending on whether t<1 or not. In those cases, I think the '?:' statement is much better and more readable than the if statement. Thus:
return t<1 ? 0 : 1;
I know the ?: operator is forbidden in some companies, and I find that a horrible thing to do. ?: usually matches much better with specifications, and it can make code so much easier to read (if used with care) ...
Let's say I have a simple function that checks a condition and returns true if the condition is true and false if the condition is false.
Is it better to use this type of code:
bool myfunction( /*parameters*/ ) {
if ( /*conditional statement*/ ) {
return true;
}
return false;
}
Or this type:
bool myfunction( /*parameters*/ ) {
if ( /*conditional statement*/ ) {
return true;
}
else return false;
}
Or does it just really not make a difference? Also, what considerations should I bear in mind when deciding whether to "if...else if" vs. "if...else" vs. "switch"?
You can also write this without any conditional at all:
bool myfunction( /*parameters*/ ) {
return /*conditional statement*/;
}
This way you avoid the conditional entirely.
Of course, if you are dealing with a different function where you need the conditional, it shouldn't make a difference. Modern compilers work well either way.
As far as using switch vs if-else, switch adds efficiency when you have many cases by allowing you to jump to a single one, making execution faster by not running all cases. At a low (hardware/compiler level), switch statements allow you to make a single check/jump, where if you had many if statements, you would need to make many checks/jumps.
It is the same. Remember whenever you say
return boolean;
the function ends and return to its calling line.
Therefore putting it inside else or just simply putting it is same.
say we want to check the prime
bool isPrime (int n){
for (int i = 2; i <= sqrt(n); i++){
if (n % i == 0)
return false;
}
return true;
}
if you see the function closely you will know if the number is divided properly with any value in range of sqrt(n) it will return false as the number is not a prime..
if it cannot be divided then the loop will end without any interference and said the number to be a prime. hence forth the function works properly.
Since neither of two given answers are hitting the nail, i will give you another one.
From the code (or compiler's) view, assuming recent compiler both versions are identical. Compiler will optimise if version to return version just fine. Difference is in debugging - the debugger you're using might not allow you to set breakpoint on return value (for example if you want to set breakpoint on only returning true values). While if version give you two return statements on different lines and any sane debugger will set breakpoint on line just fine.
Both functions are identical, regardless of any optimizations applied by the compiler, because the "else" in the second function hasn't any effect. If you leave the function as soon as the condition is met, you'll never enter the other branch in this case, so the "else" is implicit in the first version.
Hence I'd prefer the first version, because the "else" in the other one is misleading.
However, I agree with others here that this kind of function (both variants) doesn't make sense anyway, because you can simply use the plain boolean condition instead of this function, which is just a needless wrapper.
In terms of compilation the specific form you choose for if-else syntax won't make a big difference. The optimization path will usually erase any differences. Your decision should be made based on visual form instead.
As others have pointed out already, if you have a simple condition like this it's best to just return the calculation directly and avoid the if statement.
Returning directly only works if you have a boolean calculation. You might instead need to return a different type:
int foo(/*args*/) {
if(/*condition*/) {
return bar();
}
return 0;
}
Alternately you could use the ternary operator ?:, but if the expressions, it may not be as clear.
By using short returns (evaluation doesn't reach the end of the function) you can also sequence several conditions and evaluations.
int foo(/*args*/) {
if(/*condition1*/) {
return 0;
}
if(/*condition2*/) {
return 3;
}
int common = bar(/*args*/);
if(/*condition3*/) {
return 1-common;
}
return common;
}
Pick the form based on what makes the most logical sense, just ignore how this might compile. Then consider massaging the form to have the least visual complexity (avoids too much indentation or deep branching).