ternary-operator

问题 Why the ternary operator does not have blocks? In other words, why the following code does not work and reports error for {} braces? int main() { int i = 1; (i==1)?{printf("Hello\n")}:{printf("World\n")}; return 0; } EDIT Perhaps the question is misunderstood. It was: why blocks are not supported? Why only single expression? Why this is not allowed to work? int main() { int i = 1; (i==1)?{printf("Hello\n");printf("World\n");}:{printf("Bye\n");printf("World\n");}; return 0; } One reason could

问题 Hey I just came across the following statement return name != null ? name : "NA"; I am just wondering what this is called in .NET does the ? stand for i.e. then do this... ? 回答1: It's a "conditional operator" commonly known as the Ternary operator It's found in many programming languages. 回答2: Just to add to everyone else's answers, note that in... condition ? trueResult : falseResult ...only condition and either trueResult or falseResult (but not both) will be evaluated. That makes it

问题 I'm trying to use the ternary to return differing types, although I seem to be encountering some problems. My question is can the ternary operator not return differing types? // This line causes an error propertyGrid.Instance = (directoryRecord.directoryInfo != null) ? directoryRecord.directoryInfo : directoryRecord.fileInfo; // Compiles fine propertyGrid.Instance = directoryRecord.directoryInfo; // Compiles fine propertyGrid.Instance = directoryRecord.fileInfo; Error Type of conditional

问题 This question already has an answer here : Strange Java behaviour. Ternary operator (1 answer) Closed 5 years ago . I have a part of code like this: public static void main(String[] args) throws Exception { String trueValue = Boolean.TRUE.toString(); String fieldValue = null; Boolean defaultValue = null; Boolean value = (fieldValue != null ? trueValue.equalsIgnoreCase(fieldValue) : defaultValue); System.out.println(value); } When defaultValue is not equal to null the code works fine, but when

问题 This question already has answers here : Errors using ternary operator in c (5 answers) Closed 4 years ago . There are a lot of differences between C and C++ and came to stuck on one of them The same code gives an error in C while just executes fine in C++ Please explain the reason int main(void) { int a=10,b; a>=5?b=100:b=200; } The above code gives an error in C stating lvalue required while the same code compiles fine in C++ 回答1: Have a look at the operator precedence. Without an explicit

问题 For the very common case of assigning a value to a variable based on the outcome of an expression I'm a fan of ternary operators: $foo = $bar ? $a : b; However, if $bar is a relatively expensive operation and I want to assign the result of $bar to $foo if the result is truthy, this is inefficient: $foo = SomeClass::bigQuery() ? SomeClass::bigQuery() : new EmptySet(); One option is: $foo = ($result = SomeClass::bigQuery()) ? $result : new EmptySet(); But I'd rather not have the extra $result

问题 I have the following doubt: can I in some way use the conditional ternary operator into a string concatenation? I am trying to do something like this: String sql = "insert into TirConsolidatoPolizzaFondo " + "(Polizzaid, FondoID, isQuadraturaOk, ReteVendita, CodiceConferimento, PercentualeRendimentoDaInizioGestione, " + "DataInizioGestione, PercentualeRendimentoDaInizioAnno, DataInizioAnno, PercentualeRendimentoDaInizioTrimestre, " + "DataInizioTrimestre, DataCalcoloBF, ValoreNavBF,

问题 I'm missing something if someone can please explain it to me. I'm trying to re-write existing code into the ternary operator way. I'm getting the following console error : Uncaught SyntaxError: Unexpected token } which I understand there's a condition not properly formatted which I can't seem to find. So I'm not sure what I'm missing or if I maybe misunderstand something in the filter function? Isn't the ? item.verified === true not suppose to automatically return the objects that's true? var

问题 I was recently introduced to ternary operators. I managed to make it through a year and a half of CS school without a professor ever mentioning ternary operators. This is my first quarter where my professor is using them regularly. They seem great for shortening code. So, this is a question that will help me understand the bounds of ternary operators and when/how they can be used. Is there a way to shorten the following code block using one long statements using a ternary operator? if(age <

问题 Regarding conditional if/else statements, are the following examples functionally equivalent? function isEntering() { if (this.stage === 'entering') { return true; } else { return false; } } function isEntering() { if (this.stage === 'entering') { return true; } return false; } function isEntering() { if (this.stage === 'entering') { return true; } } isEntering = (this.stage === 'entering') ? true : false; If so, I'd use the most terse of the options. But only if the four are functionally