Compiletime Error
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Compile Time Error In C
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Compile Time Error Example
it only takes a minute: Sign up Compile time vs run time errors [duplicate] up vote 3 down vote favorite 1 Possible Duplicate: Runtime vs Compile time How should I know whether a specific line of code in Java may throw a compile time or run-time error? Assuming that the specific line of code anyway throws and error. java runtime compile time error and runtime error in c# compile-time share|improve this question edited May 6 '13 at 22:09 Undo♦ 18.4k157399 asked Oct 14 '12 at 12:58 uml 4503921 marked as duplicate by home, Junuxx, Denys Séguret, S.L. Barth, dSquared Oct 14 '12 at 14:35 This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question. 1 stackoverflow.com/questions/846103/runtime-vs-compile-time –Matt Whipple Oct 14 '12 at 13:01 add a comment| 5 Answers 5 active oldest votes up vote 11 down vote accepted In Eclipse, compile time errors will be underlined in red. A compile time error is an error that is detected by the compiler. Common causes for compile time errors include: Syntax errors such as missing semi-colon or use of a reserved keyword (such as 'class'). When you try and access a variable that is not in scope. When you declare multiple objects with the same name. If the compiler detects any errors during compilation it will fail to build a new assembly (or class file in Java). Even if your code
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Compile Time Error And Runtime Error In Java
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Compile Time Error Java Example
Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, compile time error and runtime error helping each other. Join them; it only takes a minute: Sign up Runtime vs Compile time up vote 179 down vote favorite 171 Can anyone please give me a good understanding of whats the difference between run-time and http://stackoverflow.com/questions/12882448/compile-time-vs-run-time-errors compile-time? compiler-construction runtime compile-time share|improve this question edited Oct 31 '09 at 13:35 e-satis 250k82236286 asked May 10 '09 at 21:06 devforall 1,807112641 add a comment| 19 Answers 19 active oldest votes up vote 253 down vote accepted The difference between compile time and run time is an example of what pointy-headed theorists call the phase distinction. It is one of the hardest concepts to learn, especially for people without much background in programming languages. To http://stackoverflow.com/questions/846103/runtime-vs-compile-time approach this problem, I find it helpful to ask What invariants does the program satisfy? What can go wrong in this phase? If the phase succeeds, what are the postconditions (what do we know)? What are the inputs and outputs, if any? Compile time The program need not satisfy any invariants. In fact, it needn't be a well-formed program at all. You could feed this HTML to the compiler and watch it barf... What can go wrong at compile time: Syntax errors Typechecking errors (Rarely) compiler crashes If the compiler succeeds, what do we know? The program was well formed---a meaningful program in whatever language. It's possible to start running the program. (The program might fail immediately, but at least we can try.) What are the inputs and outputs? Input was the program being compiled, plus any header files, interfaces, libraries, or other voodoo that it needed to import in order to get compiled. Output is hopefully assembly code or relocatable object code or even an executable program. Or if something goes wrong, output is a bunch of error messages. Run time We know nothing about the program's invariants---they are whatever the programmer put in. Run-time invariants are rarely enforced by the compiler alone; it needs help from the programmer. What can go wrong are run-time errors: Division by zero Deferencing a null pointer Running out
used is not recognised by the compiler. This is usually because the programmer has either made a simple typing slip, or because he or she has not completely understood the rules https://www.macs.hw.ac.uk/~pjbk/pathways/cpp2/node123.html of the language as they apply to the programming construct. In some sense, compile time errors are the easiest to correct, because they always result in an error message. Unless the error is so severe that the compiler cannot continue, the translation process will continue with the possibility of detecting further errors. It is possible that the errors detected are not ``genuine'' errors, but consequences of earlier time error errors. A simple example of this is the problems caused if there is an error in the declaration of a variable. The compiler will not recognise the variable as such when it is used, and it will complain about `` Undeclared variable''. In order to recover from this, many compilers make some assumption about the variable and continue, so that other errors can be found. Typically this will compile time error involve assuming that the variable has been declared of type int, and continuing. This assumption may itself cause further compilation errors if an int variable is not acceptable. A common cause of apparently correct programs causing compilation errors is a comment which is not terminated correctly. Apart from the // comment which terminates at the end of the line, C++ supports a comment that starts with /* and extends until a matching */ character pair. Omitting the closing */ causes havoc! Similar problems occur with missing quotation marks on strings " or characters '. Typing errors in variable identifiers and keywords can be difficult to spot: watch out for confusion between the letter l (el) and the digit 1 (one). Other characters that often cause errors, particularly when transcribed from handwritten notes are z and 2, s and 5, and o and 0. The compiler also distinguishes between upper and lower case letters. It is not good practice to have identifiers which only differ in the case of some letters. A good strategy for dealing with compile time errors is to identify the first error reported. Once the first error is identified, usually either in the statement in which it is reported