if-statement

'else' without a previous 'if'

由 北城余情 提交于 2020-01-11 11:07:37
问题 I am just beginning to learn C programming, so I am not really on an advanced level. Bear with me! I have this piece of code, and I guess that it is pretty easy to understand what I am trying to do. However I get an error saying the last else is called without an if before it. I suspect that the problem is my if-else statement inbetween the if and else. How would you guys solve it? int talet; scanf("%d", &talet); int i = 1; while (i <= 99) { int a; { if (i % talet == 0 || talet == (i / 10) %

What's the difference between if and elseif?

由 久未见 提交于 2020-01-11 09:24:28
问题 This should be a simple question. I have a simple if/else statement: <?php // TOP PICTURE DEFINITIONS if ( is_page('english') ) { $toppic = 'page1.png'; } if ( is_page('aboutus') ) { $toppic = 'page1.png'; } if ( is_page('newspaper') ) { $toppic = 'page1.png'; } else { $toppic = 'page1.png'; } ?> Is there a difference from ^^^ to this: <?php // TOP PICTURE DEFINITIONS if ( is_page('english') ) { $toppic = 'page1.png'; } elseif ( is_page('aboutus') ) { $toppic = 'page1.png'; } elseif ( is_page

One-line if vs && in JavaScript [closed]

由 牧云@^-^@ 提交于 2020-01-11 04:30:16
问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 4 years ago . Is there any meaningful difference between condition && console.log("this may run"); and if (condition) console.log("this may run); If not, which is a best practice? 回答1: You should use the second. Your code should say what it means. That is what is meant by writing "semantic

Batch - If, ElseIf, Else

由 ぃ、小莉子 提交于 2020-01-11 04:26:05
问题 Whats wrong with this code? IF "%language%" == "de" ( goto languageDE ) ELSE ( IF "%language%" == "en" ( goto languageEN ) ELSE ( echo Not found. ) I'm not really good in Batch.. 回答1: @echo off title Test echo Select a language. (de/en) set /p language= IF /i "%language%"=="de" goto languageDE IF /i "%language%"=="en" goto languageEN echo Not found. goto commonexit :languageDE echo German goto commonexit :languageEN echo English goto commonexit :commonexit pause The point is that batch simply

Python tuple assignment and checking in conditional statements [duplicate]

由 梦想与她 提交于 2020-01-11 03:25:34
问题 This question already has answers here : When are parentheses required around a tuple? (3 answers) Closed 5 years ago . So I stumbled into a particular behaviour of tuples in python that I was wondering if there is a particular reason for it happening. While we are perfectly capable of assigning a tuple to a variable without explicitely enclosing it in parentheses: >>> foo_bar_tuple = "foo","bar" >>> we are not able to print or check in a conditional if statement the variable containing the

How check if body has a specific class with JavaScript?

由 最后都变了- 提交于 2020-01-10 23:02:33
问题 How can I check if body has specific class? This is my case: <body class="foo foo1 foo3"></body> 回答1: function hasClass(ele,cls) { return ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)')); } if(hasClass(document.getElementById("test"), "test")){//do something}; maybe this helps you :-) With the use of jQuery it would be easier and less code but nevermind ! 回答2: There's now a super-easy way to do this: document.body.classList.contains('my-class-name') 回答3: document.getElementsByTagName(

Pro/con: Initializing a variable in a conditional statement

由 折月煮酒 提交于 2020-01-10 21:17:06
问题 In C++ you can initialize a variable in an if statement, like so: if (CThing* pThing = GetThing()) { } Why would one consider this bad or good style? What are the benefits and disadvantages? Personally i like this style because it limits the scope of the pThing variable, so it can never be used accidentally when it is NULL. However, i don't like that you can't do this: if (CThing* pThing = GetThing() && pThing->IsReallySomeThing()) { } If there's a way to make the above work, please post. But

a to the power of b without (a**b), Python

由 淺唱寂寞╮ 提交于 2020-01-10 06:10:53
问题 Struggling with an exercise that asks me to write a**b without this operator. Tried to write something myself but am not getting correct results. Instead of one value am getting two, both incorrect. Seems like the counter doesnt really increase. May I ask for help? Thanks! def powerof(base,exp): result=1 counter=0 # until counter reaches exponent, go on if counter<=exp: # result multiplies itself by base, starting at 1 result=result*base # increase counter counter=counter+1 return result

a to the power of b without (a**b), Python

由 北城余情 提交于 2020-01-10 06:10:15
问题 Struggling with an exercise that asks me to write a**b without this operator. Tried to write something myself but am not getting correct results. Instead of one value am getting two, both incorrect. Seems like the counter doesnt really increase. May I ask for help? Thanks! def powerof(base,exp): result=1 counter=0 # until counter reaches exponent, go on if counter<=exp: # result multiplies itself by base, starting at 1 result=result*base # increase counter counter=counter+1 return result

Why does Swift's optional binding succeed with 'nil' in certain cases?

由 故事扮演 提交于 2020-01-10 04:30:07
问题 Apple's Swift language documentation says that optional binding (a.k.a. if let ) will "check for a value inside an optional" and " extract that value into" a variable or constant). But this doesn't match what I'm seeing. For example var x: Int? = nil if let y1: Int? = x { println("y1 = \(y1)") // This is printed, suggesting that x is not checked "inside", but left as Optional(nil) (!= nil) } if let y2: Int? = x? { println("y2 = \(y2)") } if let y3: Int = x? { println("y3 = \(y3)") } if let y4
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