problems on using the if and else statement and updating the data.
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im appreciate for both of you on helping me in the if and else part. However, when i try to checked AddOn1 and AddOn2, i got my price 2.50 instead of 3.70.
@Mr-Nobody645 said in problems on using the if and else statement and updating the data.:
However, when i try to checked AddOn1 and AddOn2, i got my price 2.50 instead of 3.70.
That's why I wrote earlier:
In which case you'll need to test that [
if (ui-> AddOn1-> isChecked() && ui-> AddOn2-> isChecked())] before testingui-> AddOn1-> isChecked()orui-> AddOn2-> isChecked()individually. -
Do you actually want to ask some question here? What is your problem?
Do you mean to ask how to check multiple values at once in an
ifstatement?ui-> (AddOn1 + AddOn2 + AddOn3) -> isChecked()
Here is something which should work:
if (ui->AddOn1->isChecked() && ui->AddOn2->isChecked() && ui->AddOn3->isChecked())But for sake of readability and maintenance (and, to some degree, performance), I'd suggest to get state first, and check later:
const bool isAddOn1 = ui->AddOn1->isChecked(); const bool isAddOn2 = ui->AddOn2->isChecked(); const bool isAddOn3 = ui->AddOn3->isChecked(); if (isAddOn1 && isAddOn2 && isAddOn3) // ...All modernt compilers also understand
andas a synonym to&&so you can do:if (isAddOn1 and isAddOn2 and isAddOn3)@sierdzio said in problems on using the if and else statement and updating the data.:
All modernt compilers also understand
andas a synonym to&&so you can do:I am speechless! Apart from the fact that I have never heard of this (old time C/C++ programmer, now returned to new C++). And apart from the fact that introducing
andas a language keyword would potentially break one million old C/C++ programs which could have usedandas a variable?You are obviously more expert than I, but do you want to recommend this to a newbie? I have never noticed
andused in a C++ program, if OP is to produce standard code, and recognize others' code, would you not recommend sticking with&&? -
@sierdzio said in problems on using the if and else statement and updating the data.:
All modernt compilers also understand
andas a synonym to&&so you can do:I am speechless! Apart from the fact that I have never heard of this (old time C/C++ programmer, now returned to new C++). And apart from the fact that introducing
andas a language keyword would potentially break one million old C/C++ programs which could have usedandas a variable?You are obviously more expert than I, but do you want to recommend this to a newbie? I have never noticed
andused in a C++ program, if OP is to produce standard code, and recognize others' code, would you not recommend sticking with&&?@JonB apparently part of the standard since c++98
https://en.cppreference.com/w/cpp/keyword/and
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@JonB apparently part of the standard since c++98
https://en.cppreference.com/w/cpp/keyword/and@J-Hilk , @sierdzio
Absolutely shocking! I see from https://en.cppreference.com/w/cpp/language/operator_alternative that there are actually 11 new reserved words for operators. Includingnot, and even the stringcompl, which I might have used as variables and would break upgrading to C++ '98.Thinking aloud, I believe all C operators were symbols and not words, part of the charm (for right or for wrong) of the language.
With all due respect to @sierdzio's comment, which I accept & respect, I have still never seen a piece of C++ code using any of these.... [And hence would caution a beginner against adopting these.]
[C++ looks like it's trying to be a Python-wannabe ;-) ]
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@J-Hilk , @sierdzio
Absolutely shocking! I see from https://en.cppreference.com/w/cpp/language/operator_alternative that there are actually 11 new reserved words for operators. Includingnot, and even the stringcompl, which I might have used as variables and would break upgrading to C++ '98.Thinking aloud, I believe all C operators were symbols and not words, part of the charm (for right or for wrong) of the language.
With all due respect to @sierdzio's comment, which I accept & respect, I have still never seen a piece of C++ code using any of these.... [And hence would caution a beginner against adopting these.]
[C++ looks like it's trying to be a Python-wannabe ;-) ]
@JonB said in problems on using the if and else statement and updating the data.:
I have still never seen a piece of C++ code using any of these
Me neither :-)
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I have seen it but very, very rarely.
And hence would caution a beginner against adopting these
I'm split on this :D One one hand,
&&is clearly, vastly, totally the established and well-known convention practically everywhere. So using it is definitely a good idea.But on the other hand,
andis more readable and convenient. So it is also a good idea.(Z(:^
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I have seen it but very, very rarely.
And hence would caution a beginner against adopting these
I'm split on this :D One one hand,
&&is clearly, vastly, totally the established and well-known convention practically everywhere. So using it is definitely a good idea.But on the other hand,
andis more readable and convenient. So it is also a good idea.@sierdzio said in problems on using the if and else statement and updating the data.:
But on the other hand, and is more readable and convenient.
In Pascal or Python, yes. When scanning C/C++ I expect to see all operators as symbols (and not some but not others) Next C++ will be offering
begin/endfor{/}! [Some people used to do all this words-for-symbols via C#defines.] I give up on the modern world, it's all going to pot... ;-) -
@sierdzio said in problems on using the if and else statement and updating the data.:
But on the other hand, and is more readable and convenient.
In Pascal or Python, yes. When scanning C/C++ I expect to see all operators as symbols (and not some but not others) Next C++ will be offering
begin/endfor{/}! [Some people used to do all this words-for-symbols via C#defines.] I give up on the modern world, it's all going to pot... ;-)@JonB said in problems on using the if and else statement and updating the data.:
Next C++ will be offering begin/end for {/}!
you can use
{ ??< } ??> [ ??( ] ??) # ??= \ ??/ ^ ??' | ??! ~ ??-but that was removed in c++17, :)
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@JonB said in problems on using the if and else statement and updating the data.:
Next C++ will be offering begin/end for {/}!
you can use
{ ??< } ??> [ ??( ] ??) # ??= \ ??/ ^ ??' | ??! ~ ??-but that was removed in c++17, :)
@J-Hilk
but that was removed in c++17, :)
Even better --- you start using new language constructs and then they remove them so that your code gets broken!
FWIW, I note from https://en.cppreference.com/w/cpp/language/operator_alternative
There are alternative spellings for several operators and other tokens that use non-ISO646 characters.
So the motivation never was "clarity", it's to do with people having funny keyboards....
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@JonB said in problems on using the if and else statement and updating the data.:
funny keyboards
The hardware is innocent ;-P
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whats next, espousing the virtues of trigraphs?
