if else Style
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I do hope that the "==true" and "==false" are not meant literally! A programmer comparing a logical expression against "true" or "false" have not understood what is meant by a logical expression. I wonder how many of those programming that way also speak that way! "If you have a moment to spare is true, I want a talk with you", or "If the door is unlocked is false, you'll find the key under the door mat" - noone that I know speaks that way. I have met a few programmers who program that way, but I never heard any of them speak with "is true" or "is false".
Religious freedom is the freedom to say that two plus two make five.
May I please inquire how else does one evaluate a logical expression in C++. One can write
if(a)orif(!a). But these perform the same function asif(a == true)andif(a == false). if(I do not understand your meaning == true) I kindly request clarification.; -
I do hope that the "==true" and "==false" are not meant literally! A programmer comparing a logical expression against "true" or "false" have not understood what is meant by a logical expression. I wonder how many of those programming that way also speak that way! "If you have a moment to spare is true, I want a talk with you", or "If the door is unlocked is false, you'll find the key under the door mat" - noone that I know speaks that way. I have met a few programmers who program that way, but I never heard any of them speak with "is true" or "is false".
Religious freedom is the freedom to say that two plus two make five.
May I please inquire how else does one evaluate a logical expression in C++? One can write
if(a)orif(!a). But these perform the same function asif(a == true)andif(a == false). if(I do not understand your meaning == true) I kindly request clarification.; -
Agree. 8 lines is required, even for cases that could have used a simple ?:, but beyond 8 lines is a waste. Many times I have met programmers who really oppose ?: and insist that e.g.
ticketClass = (age >= 16)? adult : child;
must be written over 8 lines as
if (age >= 16)
{
ticketClass = adult;
}
else
{
ticketClass = child;
}If their productivity is measured in number of source code lines produced, I can see the justification for it, but that's all I can think of :-) Another funny thing is that those who oppose ?: frequently are proud of their creations in regular expressions.
Religious freedom is the freedom to say that two plus two make five.
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Greetings & Kind Regards I seek advice and knowledge of others' practice re/ a minor matter of style. In particular to be specific I vacillate betwixt and between two forms of final statement of if ... else ... series of statements assuming every possible condition is accounted for as shown in simple specimen / example / sample below (not snippet as it is not a snip of a larger code base). 1st style : if(expression == true) {...} else {...} 2nd style : if(expression == true) {...} else if(expression == false) {...} Note it is the final statement I am inquiring regards. Do your kind selves accept the default final result as shown in 1st style or perform explicit unnecessary test as shown in 2nd style for no other reason than to make the code self documenting and easier to understand in particular for a complex lengthy series of conditions. btw in 2nd style on occasion I add as final statement else throw who_the_heck_knows_what_happened; Thank You Kindly [edit] I have concluded kind Jacquers is quite correct. As it happened upon some coding just now of a simple series of such it was evident an explicit final test results in confusion as it is clearly not necessary. However in a lengthy complex series an explicit test makes code self documenting and so simpler to understand. KISS
condition ? f() : g();
:sigh:
CI/CD = Continuous Impediment/Continuous Despair
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May I please inquire how else does one evaluate a logical expression in C++. One can write
if(a)orif(!a). But these perform the same function asif(a == true)andif(a == false). if(I do not understand your meaning == true) I kindly request clarification.;Similarly, "if the door is locked" perform the same function as "if the door is locked is true". In speech, noone that I know of includes the "is true". So why do you program as
if (doorIsLocked == true) ...
rather than
if (doorIsLocked) ...
I see no reason for or advantage of creating a more complex logical expression, adding a second, redundant element. Both "doorIsLocked" and "doorIsLocked == true" are logical expressions, the second one just more complex than it needs to be. (Hopefully, the compiler is able to optimize the redundant element away!) If I program a test like
if (x < 10 && x < 20) ...
all programmers I know would point out that it is redundant to test for "x < 20" if you already have tested that x < 10. Adding an extra element a logical expression, to see whether a true "a" is equal to "true" (or that a false "a" is different from "true") is similarly redundant. The logical "a" expression is true or false, all by itself!
Religious freedom is the freedom to say that two plus two make five.
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condition ? f() : g();
:sigh:
CI/CD = Continuous Impediment/Continuous Despair
Your kind suggestion ? I agree : I still agree;
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Your kind suggestion ? I agree : I still agree;
-
Or even worse ...
if (age >= 16)
{
ticketClass = adult;
}
else if (age < 16)
{
ticketClass = child;
}You still do not handle the null case. True story: A friend of mine, living here in Norway, is a US citizen. She was pregnant, and planned a recreation trip out of Norway, 3 months after the expected time of birth, with her baby. Even a baby needs a passport. If you live in Norway and apply for a US passport, it can (or at least could in those days, this is 35+ years ago) take half a year to get through the paper mill. The parents didn't want to know the sex of the baby before the delivery, so when they applied for a passport for the yet unborn baby, they could not state its name. They could not state its birthday. They could not provide a photo of the passport holder. Yet, the US passport authorities did issue a passport to a person of unknown sex, unknown name, unknown birthdate, with no photo or fingerprint. I am honestly surprised that none of the systems handling that passport application went into a fatal exception :-) Or maybe they did, and it had to be debugged before the passport could be issued. Maybe, 35 years ago, US passports were essentially handled through manual procedures where exceptional conditions were handled by human brains. I am not sure that all of the fully automated passport handling systems we are using today would be able to handle that passport without stumbling and falling over.
Religious freedom is the freedom to say that two plus two make five.
-
condition ? f() : g();
:sigh:
CI/CD = Continuous Impediment/Continuous Despair
-
Or even worse ...
if (age >= 16)
{
ticketClass = adult;
}
else if (age < 16)
{
ticketClass = child;
} -
Or even worse ...
if (age >= 16)
{
ticketClass = adult;
}
else if (age < 16)
{
ticketClass = child;
} -
It could be worse, it could be raining:
//...
else if(marks > 80 && marks < 95)
{
//...
}
else if(marks > 70 && marks < 80)
{
//...
}
//..."In testa che avete, Signor di Ceprano?" -- Rigoletto
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Greetings & Kind Regards I seek advice and knowledge of others' practice re/ a minor matter of style. In particular to be specific I vacillate betwixt and between two forms of final statement of if ... else ... series of statements assuming every possible condition is accounted for as shown in simple specimen / example / sample below (not snippet as it is not a snip of a larger code base). 1st style : if(expression == true) {...} else {...} 2nd style : if(expression == true) {...} else if(expression == false) {...} Note it is the final statement I am inquiring regards. Do your kind selves accept the default final result as shown in 1st style or perform explicit unnecessary test as shown in 2nd style for no other reason than to make the code self documenting and easier to understand in particular for a complex lengthy series of conditions. btw in 2nd style on occasion I add as final statement else throw who_the_heck_knows_what_happened; Thank You Kindly [edit] I have concluded kind Jacquers is quite correct. As it happened upon some coding just now of a simple series of such it was evident an explicit final test results in confusion as it is clearly not necessary. However in a lengthy complex series an explicit test makes code self documenting and so simpler to understand. KISS
As others have said, it depends on the context. I prefer a ternary operator if I must choose between returning one of two results:
Foo foo = (condition ? Foo1 : Foo2);
For choosing different actions, I prefer the if/then/else style, even if it would be possible to write this as a ternary expression:
if (condition)
{
expressions1;
}
else
{
expressions2;
}A "cascading" if/then/else is useful for subordinate cases:
if (condition1)
{
expressions1;
}
else
{
if (condition2)
{
expressions2;
}
else
{
expressions3;
}
}Note that there is angoing debate whether good style requires that one wrap even single expressions in curly brackets. ( {...} }. If is usually not required by the language, but can help clarify the flow. Note that there are cases where a "cascading ternary operator" can also be useful, and actually clearer than the "cascading if/then/else".
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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Greetings & Kind Regards I seek advice and knowledge of others' practice re/ a minor matter of style. In particular to be specific I vacillate betwixt and between two forms of final statement of if ... else ... series of statements assuming every possible condition is accounted for as shown in simple specimen / example / sample below (not snippet as it is not a snip of a larger code base). 1st style : if(expression == true) {...} else {...} 2nd style : if(expression == true) {...} else if(expression == false) {...} Note it is the final statement I am inquiring regards. Do your kind selves accept the default final result as shown in 1st style or perform explicit unnecessary test as shown in 2nd style for no other reason than to make the code self documenting and easier to understand in particular for a complex lengthy series of conditions. btw in 2nd style on occasion I add as final statement else throw who_the_heck_knows_what_happened; Thank You Kindly [edit] I have concluded kind Jacquers is quite correct. As it happened upon some coding just now of a simple series of such it was evident an explicit final test results in confusion as it is clearly not necessary. However in a lengthy complex series an explicit test makes code self documenting and so simpler to understand. KISS
For a "minor matter of style", this got a lot of responses! I use style#1 if it's clear that all possibilities have been exhausted, and the
?operator if possible. But if there's a sequence of nestedifstatements and there's any possibility that not all combinations have been accounted for, I use style#2 with thethrowstatement after theelse. Defensive coding takes very little time compared to that which is otherwise wasted hunting down mysterious bugs.Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
For a "minor matter of style", this got a lot of responses! I use style#1 if it's clear that all possibilities have been exhausted, and the
?operator if possible. But if there's a sequence of nestedifstatements and there's any possibility that not all combinations have been accounted for, I use style#2 with thethrowstatement after theelse. Defensive coding takes very little time compared to that which is otherwise wasted hunting down mysterious bugs.Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
Similarly, "if the door is locked" perform the same function as "if the door is locked is true". In speech, noone that I know of includes the "is true". So why do you program as
if (doorIsLocked == true) ...
rather than
if (doorIsLocked) ...
I see no reason for or advantage of creating a more complex logical expression, adding a second, redundant element. Both "doorIsLocked" and "doorIsLocked == true" are logical expressions, the second one just more complex than it needs to be. (Hopefully, the compiler is able to optimize the redundant element away!) If I program a test like
if (x < 10 && x < 20) ...
all programmers I know would point out that it is redundant to test for "x < 20" if you already have tested that x < 10. Adding an extra element a logical expression, to see whether a true "a" is equal to "true" (or that a false "a" is different from "true") is similarly redundant. The logical "a" expression is true or false, all by itself!
Religious freedom is the freedom to say that two plus two make five.
trønderen wrote:
Religious freedom is the freedom to say that two plus two make five.
Incorrect. Two plus two making five is provably incorrect. Religious freedom is the freedom to believe things that cannot be proven.
The difficult we do right away... ...the impossible takes slightly longer.
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trønderen wrote:
Religious freedom is the freedom to say that two plus two make five.
Incorrect. Two plus two making five is provably incorrect. Religious freedom is the freedom to believe things that cannot be proven.
The difficult we do right away... ...the impossible takes slightly longer.
Religious freedom is the freedom to be irrational. If you reject all irrationality, then you reject religion. We cannot forbid irrationality and still claim that we have full religious freedom. Using "two plus two make five" as an example is a way to make the irrationality (very) explicit.
Religious freedom is the freedom to say that two plus two make five.
-
But you don't really mean something like?
if (expression)
{
}
else if (!expression)
{
}
else
{
throw(this and that);
}No
throwhere. It's clear that something above will get executed, and the(!expression)is also redundant.Robust Services Core | Software Techniques for Lemmings | Articles
The fox knows many things, but the hedgehog knows one big thing. -
You still do not handle the null case. True story: A friend of mine, living here in Norway, is a US citizen. She was pregnant, and planned a recreation trip out of Norway, 3 months after the expected time of birth, with her baby. Even a baby needs a passport. If you live in Norway and apply for a US passport, it can (or at least could in those days, this is 35+ years ago) take half a year to get through the paper mill. The parents didn't want to know the sex of the baby before the delivery, so when they applied for a passport for the yet unborn baby, they could not state its name. They could not state its birthday. They could not provide a photo of the passport holder. Yet, the US passport authorities did issue a passport to a person of unknown sex, unknown name, unknown birthdate, with no photo or fingerprint. I am honestly surprised that none of the systems handling that passport application went into a fatal exception :-) Or maybe they did, and it had to be debugged before the passport could be issued. Maybe, 35 years ago, US passports were essentially handled through manual procedures where exceptional conditions were handled by human brains. I am not sure that all of the fully automated passport handling systems we are using today would be able to handle that passport without stumbling and falling over.
Religious freedom is the freedom to say that two plus two make five.
trønderen wrote:
this is 35+ years ago ... surprised that none of the systems handling that passport application went into a fatal exception
That long ago might not have been a system. Might have been a person. Could also just be a special case that they handle.
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Similarly, "if the door is locked" perform the same function as "if the door is locked is true". In speech, noone that I know of includes the "is true". So why do you program as
if (doorIsLocked == true) ...
rather than
if (doorIsLocked) ...
I see no reason for or advantage of creating a more complex logical expression, adding a second, redundant element. Both "doorIsLocked" and "doorIsLocked == true" are logical expressions, the second one just more complex than it needs to be. (Hopefully, the compiler is able to optimize the redundant element away!) If I program a test like
if (x < 10 && x < 20) ...
all programmers I know would point out that it is redundant to test for "x < 20" if you already have tested that x < 10. Adding an extra element a logical expression, to see whether a true "a" is equal to "true" (or that a false "a" is different from "true") is similarly redundant. The logical "a" expression is true or false, all by itself!
Religious freedom is the freedom to say that two plus two make five.
Just noting that the semantics of how a logical expression is resolved in C++ is different than in C#/Java. So the following is valid in C/C++
int v = 0;
if (v) {}
else {}Because of operator overloading in C++ (to be fair it has been long time since I did this) I believe there can be situations where one must explicitly use the following. Leaving it out at a minimum might lead to a compiler error. I can't visualize a case where it would not lead to a compiler error but might be one and then it would lead to a different and incorrect result at least compared to the code below.
if (p == true) ...
