While playing with NLP I've been encountered with little problem:
switch(var1)
{
case Variant1_1:
if( cond1 )
{
if( cond2 )
{
if( cond3 )
{
switch(var2)
{
case Variant2_1:
return someExpression;
// another five-six cases
default:
return;
}
}
else // cond3
{
switch(var2)
{
case Variant2_1:
return someExpression;
// another five-six cases
default:
return;
}
}
}
else // cond2
{
if( cond3 )
{
switch(var2)
{
case Variant2_1:
return someExpression;
// another five-six cases
default:
return;
}
}
else // cond3
{
switch(var2)
{
case Variant2_1:
return someExpression;
// another five-six cases
default:
return;
}
}
}
}
else // cond1
{
// same thing
}
break;
case Variant1_2:
// same gigantic tree
break;
case Variant1_3:
// here too
break;
default:
return;
}
What alternatives are for such "computational tree"? The only thing that comes to my mind - some tree container with function pointers as leaves and a great deal of little functions.
(tongue in cheek) Every time you encounter a switch statement in a C++ program, you know that you've missed an inheritance opportunity.
The two ways I know to refactor multiple parallel switches are (1) building a multi-dimension array of function pointers, and (2) using a variation of the visitor pattern.
A nice workaround is using a matrix.
This will work well if you know that all the conditions will be evaluated anyway.
Make a multi-dimensional array that will map the true-false values to the handling functions.
Arrayswitch[var1][cond1][cond2][cond3][var2]();
I start looking for a data-driven approach when code starts to look like this. It may be as simple as a table or perhaps a tree with function pointers as you've suggested.
If this is a hand-rolled parser of some sort, you might want to look into some references on parsing for ideas on how to use a grammar definition to do the parsing (either by interpretting the grammar on demand, or by using a code-generation tool that uses the grammar as input).
I often hand-roll recursive descent parsers. Typically, I create a class that holds the state, expose one public "Parse" function, and implement each rule as a private member function. These member functions are small and explicitly named, so the code becomes quite readable. It's also very easy to write tests for it.
Polymorphism and good code design.
http://www.cs.bu.edu/teaching/cpp/polymorphism/intro/
What you're describing is what the compiler will make out of your code anyway :) So you're essentially proposing a nested programming language, which brings about Greenspun's law: "Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp."
There are ways of writing this code better to express your conditions. when you have a lot of nested if() { if () { if() } } }s, usually just writing if (!condition) break; or other escaping method, simplifies the code. not always but a lot of times.
Related
In C and in javascript I enjoy the ability to write this kind of thing and have it just work.
while (a)
{
ctx: while(b)
{
while (c)
{
if(d) break ctx;
...
}
}
...
}
Perhaps I'm just confused about C++ versions but I get this kind of error in g++:
error: expected ‘;’ before ‘ctx’
break ctx;
error: ‘ctx’ was not declared in this scope
warning: label ‘ctx’ defined but not used [-Wunused-label]
ctx:
C++ appears to refuse letting me write this code.
C++ has added lambdas/closures that potentially would let me do this but I'm not quite sure how they would work in this case.
Using try throw catch is the closest construct I can think of that produces this behavior but the sloppiness of using an error system when none should be needed concerns me (Also they are slow I hear).
I'm tempted to just wrap it in extern C except I'm relying on c++ library's completely for the entire project so this also feels sloppy.
Is a try block or just rewriting my only options?
Neither C nor C++ have a labelled break statement (You're probably using a language extension, rather than standard C).
Instead, you can use goto to break out of a nested loop.
while (a)
{
while(b)
{
while (c)
{
if(d)
goto break_b;
}
}
break_b:
// ...
}
I was able to use goto to solve this... I though it was a banned construct in c++?
No. goto is not "banned" in C++.
This is a completely fine way to use goto. There doesn't exist an equivalent structured control statement.
lambdas/closures [...] potentially would let me do this but I'm not quite sure how they would work in this case.
If you are allergic to goto, then you can indeed use a lambda, but I don't see it providing any additional readability:
while (a)
{
[&](){
while(b)
{
while (c)
{
if(d)
return;
}
}
}();
// ...
}
Instead of a lambda, you can use a named function. But in that case you need to pass any variables (such as b, c and d) as arguments (assuming they're not globals).
Yet another way is an extra variable:
while (a)
{
bool break_b = false;
while(b)
{
while (c)
{
if(d) {
break_b = true;
break;
}
}
if (break_b)
break;
}
// ...
}
Of these three methods, I recommend goto, since it's the most readable. Except in the case the actual inner loop omitted from the example is very long, in which case a separate function might be better.
As has already been pointed out by others, goto would be a way to do exactly what you're asking for.
That being said, I would argue that, before asking the question of how to break out of a massively-complicated control flow structure, you should first ask yourself why there is a massively-complicated flow structure to begin with. What is going on in these loops? Should whatever is going on in each of these loops not better be moved into its own function? For example, instead of
while (a)
{
ctx: while (b)
{
while (c)
{
if (d) goto ctx;
…
}
}
…
}
why not
bool doC()
{
while (c)
{
if (d)
return false;
…
}
return true;
}
void doB()
{
while (b && doC());
}
and then
while (a)
{
doB();
…
}
Replacing the break with a goto here is not advisable. There can be issues wrt constructors and destructors not being called correctly. Whilst goto still exists in C++, it's really not something you want to use unless you really know what you're doing! A safer option would be to use a try-catch block. A better approach would be to re-factor your algorithm (currently it's O(N^3), which should really be ringing some alarm bells!)
while (a)
{
try
{
while(b)
{
while (c)
{
if(d) throw;
}
}
}
catch(...)
{
}
}
Currently I am having a function which has two arguments of type enums, the function requires to compare both and do particular task
example:
void set_Test_Status(Tests TestName, Status TestStatus)
{
switch(TestName)
{
case Tests::Test1:
{
switch(TestStatus)
{
case TestStatus::St1:
//Rest of Code
}
}
//Rest of Code
}
}
is it a good programming practice? or is there any alternative method or style of coding that i should be aware of? Thank you!
Edit:
Finally after trial and error, I did this. First i saw the maximum and minimum items in each enums, In my case TestName were 6 and TestStatus had 3. I created 3 functions setStatusRunning(Tests TestName), setStatusSelected(Tests TestName) and setStatusFinished(Tests TestName) and in set_Test_status, using switch(TestName) i check which function should be called and then called the appropriate functions. The reason i had to make set_Test_Status in the first place was to make easy for other classes, since i made set_Test_Status public and the other 3 as private.
It is truly a matter of opinion as having nested switch statements is valid c++ code. Some may not have problems with it while others may argue that it can be confusing.
My advice would be on the lines of this; if the code blocks within the case statements are short such as 1-2 lines and they are fairly easy to read and follow, then there should be nothing wrong with it. However, if the code is quite cumbersome and the nested switch statements spans well over 50 to 100+ lines then I would suggest refining your code and make functions out of them.
Examples:
// should be okay
unsigned int outerSwitch = someValue();
unsigned int innerSwitch = someOtherValue();
switch ( outerSwitch ) {
case 1: {
switch ( innerSwitch ) {
case 1 : {
// 1 or 2 lines okay;
}
case 2 : {
// 1 or 2 lines okay;
}
case 3 : {
// 1 or 2 lines okay;
}
default : {
}
} // inner switch when outer switch case = 1
}
case 2: {
// Same as case 1
}
case 3: {
// Same as case 1
}
default: {
}
} // outer switch
But as you have seen above with just 3 cases to the outer and inner; it gets very long very quickly and I haven't even expanded them all. So this can be frowned upon.
You can have a single switch as others have suggested that calls a specific function to that switch then within that function it has its own switch statement like this:
unsigned int someFuncA( unsigned int someVal ) {
switch ( someVal ) {
case 1 : {
// do this
// return that;
}
case 2: {
// ... etc.
}
} // switch
}
unsigned int someFuncB( int someVal ) {
// similar to someFuncA();
}
unsigned int someFuncC( int someVal ) {
// similar to someFuncA();
}
unsigned int switchValue = someValue();
unsigned int innerValue = someOtherFunction();
unsigned int temp = 0;
switch( switchValue ) {
case 1 : {
temp = someFuncA( innerValue );
// either return temp, break, continue, or fall through
}
case 2 : {
temp = someFuncB( innerValue );
// same as above
case 3 : {
temp = someFuncC( innerValue );
// same as above
}
default : {
// default stuff here
}
} // switch
Comparing the two you will see that the 2nd version is easier to read and less cumbersome than the 1st. Yes the first version is valid legal C++ code, but is frowned upon because of how messy it can easily and quickly get. So where ever you can; turn that code into a function that is designed to do just that one thing.
EDIT
Another possibility is to design specific functions to do a task and as you said that your function takes 2 different enumeration values, you can look up the concept of functions that are designed to take bit flags. You will see this kind of code quite a bit in windows programming as well as OpenGL.
Another option is this: consider that fact you have an outer control switch, and inner control switch. Even if you have multiple cases, each case is independent with a specific unique ID. The same can be said for the inner switch cases. Knowing this you can create an associative mapping of all the statements in a combined matter using std::multimap<unsigned, unsigned> testCases and with this lookup table you can have it in a single statement with independent function calls to each map entry. cppreference : std::multimap
Your map might look like this:
testCases[1][1];
testCases[1][2];
testCases[1][3];
testCases[2][1];
testCases[2][2];
testCases[2][3];
testCases[3][1];
testCases[3][2];
testCases[3][3];
Where each index of the map is the logic or calculation you want to perform.
It can be quite confusing for someone reading the code-- indentation helps, but it can still be difficult to follow where the case and switch statements start and end. Most IDEs have support for finding a matching brace, but finding a matching break isn't generally a thing, so it can be difficult to even see where a case statement ends. (And technically case doesn't define scope whereas braces do, so it doesn't even have an end.)
If you get misaligned braces or accidentally mismatch where they should be, you can have odd things happen. Languages like Ada try to prevent that with strongly typed English-language specifiers.
If you are doing a lot of sub-switches, I would put them into another function and call it with the information it needs, then you could do a switch statement inside the method which is more modular, separate scope and clear what is going on.
A good practice to keep code concise is to do only one thing in a function. Using a switch already is a smell that your function is going to do different things. It all depend of your specific case.
One thing to look at is: is it coherent to manage all these cases in one class. Should you have one class per possibility, with an interface forcing to implement a function, instead of doing all the possibilities in a switch case.
In case you want to keep the switch, a good practice would be to not put code in it other than the switch. Each case just calls a function. This will already make stuff more readable.
Finally, are you using all the cases? If no, you code could be more clear by just implementing the pairs of values that you need:
if(TestName == Tests::Test1 && TestStatus == TestStatus::St1)
{
doThing();
}
To summarize:
This might be a smell that your code needs to be split in more classes to have only one responsibility per class (too many if and/or too many switches ar a sign of that). If you are sure that you need a switch, keep it as simple and clear as possible
do{...} while(0);
the usage of do{}while(0); in my coding is used because, i do not want to use long if else nested conditional statements. I eventually give an break at the time of failure and move out of the loop, with a assurance that my function would have been traversed at least 1 time.
Now, the problem comes with the code warning tools, I am getting a warning at the usage of do{...}while(0);
the usage of nested if(){} else{} is less readable, high complex. and lets the code to be having dead code.
if i exclude nested if(){} else{} and do{} while(0); , do we left part with some other way to make code readable with understandable logic;
if(status_of_funcA_ok != funcA())
{ //failure}
else if (status_of_funcB_ok != funcB())
{//failure}
else if (status_of_funcC_ok != funcC())
else
{//Great}
do{
if(status_of_funcA_ok != funcA())
break;
if (status_of_funcB_ok != funcB())
break;
if (status_of_funcC_ok != funcC())
break;
}while(0);
Move the complete logic of the do while{0} loop to a function, and replace the break with return. And call the function, instead of the loop.
You will not have to worry about the beauty.
The compiler also doesn't have to complain about the do while{0}.
All the more, by adding a bit of modularity, the program might be a little more readable.
In any case, before doing this, it would be nice to check whether your compiler is in an extremely pedantic mode, and you might want to turn that off. That might take the warning away.
ss.
PS: You don't seem to need a return value for the function, but you could have that to get a clue of which function was successful.
I am using this pattern too, for those who wonder, here's an abstract example:
do // while(0) for break
{
state1 = 0;
if (cond1())
{
if (cond2())
break;
state1 = opA();
}
if (cond3() || state1 && state1->cond4())
break;
...
Triumph(state1, ...);
// often here: return
}
Failure(state1, ...);
I consider this valid in the following circumstances:
you have a long-ish sequence (say, >~half a dozen of conditions)
the conditions are complex, and you use / build up significant state, so you can't
isolate the elements into functions
you are in an exception-unfriendly environment, or your break-ing code path is
not actually an exception
What you can do about it:
Silence the warning. It is just a warning, after all; and I don't see a "typical mistake" (like typing 0 instead of your condition) that would be caught by this warning.
[edit] Now, that was silly. the typical mistake that you catch with the warning is e.g. while (a1!=a1) instead of while (a1!=a2).[/edit]
Break into functions, move state to a class
this would transform above code to:
struct Garbler
{
State1 state1;
bool Step1()
{
state1 = 0;
if (cond1())
{
if (cond2())
return false;
state1 = opA();
}
return true;
}
bool Step2()
{
return cond3() || state1 && state1->cond4();
}
..
void Run()
{
if (Step1() && Step2() && ... && Step23())
Triumph(state1, ...);
else
Failure(state1, ...);
}
}
This is arguably less readable, worse is that you pull apart the sequence, which might lead to a very questionable class (where members may be called only in a certain order).
Scopeguards
This may allow to transform the breaks into early returns, which are more acceptable:
state1 = 0;
ScopeGuard gFailure = MakeGuard(&Failure, ByRef(state1), ...);
if (cond1())
{
if (cond2())
return;
state1 = opA();
}
if (cond3() || state1 && state1->cond4())
return;
// everything went ok, we can dismiss the scopeguard
gFailure.Dismiss();
Triumph(state1, ...);
They can be more elegantly written in C++0x, preserve the flow, but the solution isn't that flexible either, e.g. when Failure() cannot be isolated easily into a single function.
Nested nested if-else statements can become quite unreadable, but I think using do {..} while(0); as a replacement would be much worse. It is very unconventional and anybody else reading it would not really associate it with if-else statements.
There are a few things you can do to make nested if-else statements more readable. A few suggestions are:
optimize your logic - sometimes you can do away with a lot of if clauses when you 'refactor' your logic ex. grouping identical items.
use switch() - switch is generally more readable compared to if-else statements. You can associate an enum to each case and you can switch this.
encapsulate complicated logic with functions
You can use goto instead of do {} while(0) and break. This is not readable and not good practice either though. I think for each specific case there is a better way to avoid deep if/else structures. For example, sometimes using function calls can help:
for example instead of:
if(status_of_funcA_ok != funcA())
{ //failure}
else if (status_of_funcB_ok != funcB())
{//failure}
else if (status_of_funcC_ok != funcC())
else
{//Great}
you can write:
if (check_funcs() == 0) {
great();
}
int check_funcs() {
if (status_of_funcA_ok != funcA())
return -1;
if (if(status_of_funcB_ok != funcB()))
return -2;
if (if(status_of_funcC_ok != funcC()))
return -3;
return 0; /* great */
}
Sometimes, you can use exit().
Also, in c++ you can use throw() and try/catch:
try {
/* */
throw (this error);
/* */
throw (that error);
} catch (this error) {
} catch (that error) {
}
If there are more conditions to check avoid using if{} else{},
best practice is to Replace if else conditions with switch case
In a situation where a variable could have two different values, and you do something if its one, something differnent if its the other, would you just do:
if(myVariable == FIRST_POSSIBLE_VALUE) { ... }
else { ... }
or would you do:
if(myVariable == FIRST_POSSIBLE_VALUE) { ... }
else if (myVariable == SECOND_POSSIBLE_VALUE) { ... }
for clarity, in a situation where a reader wouldn't necessarily be able to tell that they do the same thing (but the else if does a "needless" expression)?
So what would you do?
Thanks!
EDIT: There is actually about a lot more different options for something like this: ternary operator, if-else, if-elseif, if-elseif-else, -if-else(with assert), switch. Each one has its place, but its hard to decide..
I always prefer just plain else when there is no other possible state of the variable(ie, checking for null and all that). I may add a comment saying what the variable is if it isn't the first conditional, but that is only in cases where its like
if(color==red){
....
}else{ //our theme only allows for red and yellow, so the color must be yellow.
....
}
Also, this saves some time for the processor cause it won't have to check a useless variable(or worse in OOP, where checking that variable can take quite a few dereferences, function calls, and memory reads)
I never do something like
if(file.is_open==1){
....
}else if(file.is_open==0){
....
}
as is_open is a boolean, it is pointless to specify that because the only option left is 0, also this can save a little bit of typing when you must refactor your code to use is_open() instead, as now you only must change one line instead of two.
and 'else if' statements I think should be turned to switches if there is more than 1 'else if', unless of course the language makes it impossible(such as how C can't handle strings in switches)
Else is a default. Meaning that there are either a large number of possibilities for the data, or that it is unexpected data.
I go by the basic rule: If there is a parameter that can be met, use else if, and if there isn't, use else. I normally use else's for errors.
I only use the if-else for boolean checks, that means that if the expression doesn't match there only can be the else. Or i want to take everything with the else: think of it like default.
If you want to check enumeration or something, you should try check this via switch statement, if possible in your language.
In Java it's not possible to use a switch for Strings. So you could use something like this:
if(string.equals("foo")) {
// first case
} else if(string.equals("bar")) {
// second case
} else {
throw IllegalArgumentException(" ... ");
// or log it
}
If you're not sure that your check can't be extended, you should if you can provide an default way.
Isn't this what assert was made for?
if (condition1) { ... }
else { assert(condition2); }
This can be expanded for three-state logic, too.
if (condition1) { ... }
elsif (condition2) { ... }
else { assert(condition3); }
Using assert makes your code readable, easy to maintain, and clear. That being said, asserts and comments are almost interchangeable.
Sometimes the condition of the else statement is very obvious. For example
if(user.IsNew) { } else { /*in this case user.IsNew != true*/ }
But in some other cases the else isn't that obvious and it is better to clarify the else condition. This is also more future proof in case some other possible conditions are added.
Furthermore you are able to insert an exception in the (last) else to inform about unimplemented cases. This can be very useful when the for example backend and frontend are separated and somebody adds a new value to an enumerator (or when using text keys a new key is introduced) you will receive an error when the new value is first used. When not using if else if you won't see what happened and that could make debugging pretty hard.
if(user.SelectedStyle == Styles.Red) {
} else if(user.SelectedStyle == Styles.Basic) {
} else {
throw new Exception("Not implemented");
}
In the case above a new Style (for example Style.Blue) will cause your application to throw an exception.
It's really a matter of style and your own mental view of the world. The glass is BOTH half empty and half full, but you can get the darnedest arguments going about it.
If the boolean tests are all of the same type, a switch statement is best.
If not, I'd recommend leaving out the additional test but insert a comment about the operational meaning of falling through into that last statement. See Gertjan's comment, above.
When your input can be clearly separate into distinct cases, I feel it is mostly nicer to explicitly state what those cases are, for example if you are expecting 'n' to be a number between 0 and 100, and you have 3 cases:
if (n >= 0 && n < 30) {
case1();
} else if (n >=30 && n < 70) {
case2();
} else if (n >=70 && n < 100) {
case3();
}
in some situations the 'else' case is good for error checking
} else {
error("n should be between 0 and 100");
}
if your data is checked for erroneous values earlier, then there may be a case to use else for the final case, to provide a small performance improvement in languages like C:
} else { // (n >= 70 && n < 100)
case3();
}
but this is only necessary due to some languages inability to express the domain of a function, in languages where the domain can be expressed clearly, the optimiser should add this performance benefit for you, allowing you to be specific in your code, and making it easier to add more cases later
... of course this is an art, not a science, and in some cases you can't follow the hard-and-fast rule, I frequently find myself writing code like:
if (p == NULL) {
doSomething();
} else {
doSomethingElse();
}
...justified by the fact that is very obvious and implicit from the first if condition what the else is used for.
else was invented and is used for good reason. Where you use it should be dictated by the logic that you trying to achieve, not a contrived sense of style.
Some argue that it is more self-documenting by using explicit conditions in an else if; however, this may lead to gaps in logic with default or catch all conditions.
Also, some say that it is easier to modify in the future. This argument is bunk. Using design patterns and writing modular code is something that is easier to modify in the future, writing one line shouldn't qualify for these kinds of statements.
It depends on the situation. Do you only want to take action if certain criteria are met, or is there a special case for one value and another set of logic for any other value?
I just hope the following doesn't seem to you like redundant jabber :)
Anyway, there is that:
for (p = fmt; *p; p++) {
if (*p != '%') {
putchar(*p);
continue;
}
switch (*++p) {
/* Some cases here */
...
}
}
And I wondered why the writer (Kernighan / Ritchie) used the continue in the if statement.
I thought it was for the mere reason that he deemed it would be more elegant than indenting the whole switch under an else statement, what do you think?
Probably. The human brain has limited stack space, making it difficult to deal with deeply nested structures. Anything that flattens the information we're expected to parse makes it easier to understand.
Similarly, I normally prefer this:
bool foo(int arg)
{
if(!arg) {
/* arg can't be 0 */
return false;
}
/* Do some work */
return true;
}
To this:
bool foo(int arg)
{
if(!arg) {
/* arg can't be 0 */
return false;
} else {
/* Do some work */
return true;
}
}
Or worse, to this:
bool foo(int arg)
{
if(arg) {
/* Do some work */
return true;
} else {
/* arg can't be 0 */
return false;
}
}
In the last example, the part that does the work might be quite long. By the time the reader gets to the else clause, he may not remember how he got there.
Putting the bail out conditions as close to the beginning helps to assure that people who try to call your functions will have a good idea of what inputs the function expects.
Also, as others pointed out, the continue makes it clear that there's no need to read further into the code inside the loop to determine whether any more processing is done after that point for this case, making the code easier to follow. Again, the fewer things you force the reader to keep track of, the better.
Because with the continue it is clear that the code is done for this loop iteration. If a else would have been used you had also to check if there is no code after the else.
I think it is general a good habit to exit a context as soon as possible because this leads to much clearer code.
For example:
if(arg1 == NULL)
return;
if(arg2 == NULL)
return;
//Do some stuff
vs.
if(arg1 != null)
{
if(arg2 != null)
{
//Do some stuff
}
}
It is just so much easier to read when it's put like this.
Are we done here with this iteration through the loop? Yes? So let us continue with the next iteration.
I think that he would have reasons enough to indent the code under the switch, and indenting the entire meat of the function is quite wasteful of horizontal space. At the time the code was written, I imagine 80 character widths were still popular.
I don't think it is difficult to understand, but I do think that it's quite nice to mention what you DON'T do immediately, and then GTFO.
There are always many ways to write code like this -
Putting the entire switch inside an else statement would be perfectly valid. I suppose the reason they did it this way ~may~ have been just the way they were thinking at the time:
"if the value at p does not equal '%', put then continue on."
If you have switch under an else, it may not have been as obvious to the writer that you were jumping to the next iteration in that specific case.
This is completely personal style choices, though. I wouldn't worry too much - just write it in a way that makes the most sense to you and your team.
I agree.
But you can't look at it as a "mere reason", it's actually a pretty good reason, because it reduces the over all complexity of the code. Making it shorter and easier to read and understand.
If you use an else then everything inside the else needs to be indented:
if ()
{
doA();
}
else
{
doB();
if ()
{
doC();
}
else
{
doD()
}
}
If you use continue then you don't need to indent:
if ()
{
doA()
continue;
}
doB();
if ()
{
doC();
continue;
}
doD();
Also, continue means that I can stop thinking about that case: for example, if I see else then perhaps there'll be more processing of the '%' case later in the loop, i.e. at the end of the else statement; whereas on seeing continue I know instantly that the processing of the '%' case in the loop is completely finished.
The most probable reason is that the switch that follows is rather long - this looks like printf format parsing.
There could be more that one reason to continue/break a loop. So it would look next:
loop
{
if (cond1)
{
if (cond2)
{
if (cond2)
{
more conditions...
}
}
}
else
{
the loop action
}
}
IMHO it's not so elegant and readable as the loop in your example, e.g:
loop
{
if (cond1)
continue;
if (cond2)
continue;
if (cond2)
continue;
if( more conditions...)
continue;
the loop action
}
And you don't even need to understand all structure of all "if"s (it could be much more complex) to understand the loop logic.
P.S. just for the case: I don't think the authors thought about how to write this loop, they just wrote it:)
I stick to Dijkstra's teachings: goto is harmful. And continue/break are goto's little brothers.
If the problem is that you're indenting the code too much, the solution is not putting a continue in the loop, but reducing the complexity by separating the code in different functions or thinking about a better way of organizing it.
For example, #Kamarey snippet would be even clearer like this:
loop
{
if (!(cond1 ||
cond2 ||
cond2 ||
...))
{
the loop actions;
}
}
or #Ori Pessach example could be expressed like:
bool foo(int arg)
{
if(arg) {
/*do some work*/
}
return arg != 0;
}
In brief, usually I can't find a good enough reason to use non structured programming constructs (maybe for some cleanup codes in a very limited ocasions...)
Well, I wrote C programs for about 11 years and I had to read 5 times your piece of code to understand it !
Kernighan and Ritchie were active in the sixties. At that time, being able to understand a piece of code was not relevant. Being able to write code that fit in 16 Ko was.
So I'm not suprised. C is a terrible language when your teatchers are K & R. Just look at realloc : who would know code something like that today ? In the '60ies, it was all the rage, but it is now appalling, at least :o)