运行时vs.编译时

运行时和编译时的区别是什么?

当前回答

嗯，好吧，运行时是用来描述程序运行时发生的事情。

编译时间用来描述在构建程序(通常由编译器)时发生的事情。

2009-05-10 21:09:01

其他回答

public class RuntimeVsCompileTime {

    public static void main(String[] args) {
        
        //test(new D()); COMPILETIME ERROR
        /**
         * Compiler knows that B is not an instance of A
         */
        test(new B());
    }
    
    /**
     * compiler has no hint whether the actual type is A, B or C
     * C c = (C)a; will be checked during runtime
     * @param a
     */
    public static void test(A a) {
        C c = (C)a;//RUNTIME ERROR
    }

}

    class A{
    
}

    class B extends A{
    
}

    class C extends A{
    
}

    class D{
    
}

2019-07-25 04:41:39

编译时和运行时之间的差异就是精明的理论家所说的阶段差异的一个例子。它是最难学习的概念之一，特别是对于没有太多编程语言背景的人来说。要解决这个问题，我发现问一下很有帮助

程序满足哪些不变量? 在这个阶段会出现什么问题? 如果阶段成功，后置条件是什么(我们知道什么)? 输入和输出是什么(如果有的话)?

编译时

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.

运行时

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 Dereferencing a null pointer Running out of memory Also there can be errors that are detected by the program itself: Trying to open a file that isn't there Trying find a web page and discovering that an alleged URL is not well formed If run-time succeeds, the program finishes (or keeps going) without crashing. Inputs and outputs are entirely up to the programmer. Files, windows on the screen, network packets, jobs sent to the printer, you name it. If the program launches missiles, that's an output, and it happens only at run time :-)

2009-05-11 01:13:45

以下是前面类似的问题的答案，运行时错误和编译器错误的区别是什么?

编译/编译时/语法/语义错误:编译或编译时错误是由于键入错误而发生的错误，如果我们没有遵循任何编程语言的正确语法和语义，那么编译器就会抛出编译时错误。除非您删除所有语法错误或调试编译时错误，否则它们不会让您的程序执行一行。例如:在C语言中缺少分号或将int错误地输入为int。

运行时错误:运行时错误是指程序处于运行状态时产生的错误。这些类型的错误将导致您的程序出乎意料地运行，甚至可能杀死您的程序。它们通常被称为例外。示例:假设您正在读取一个不存在的文件，将导致运行时错误。

阅读更多关于所有编程错误

2015-05-25 05:41:48

我们可以将其分为两大类静态绑定和动态绑定。它取决于何时与相应值绑定。如果引用是在编译时解析的，那么它是静态绑定;如果引用是在运行时解析的，那么它是动态绑定。静态绑定和动态绑定又称早期绑定和后期绑定。有时也称为静态多态和动态多态。

约瑟夫Kulandai‏。

2014-06-07 19:48:17

下面是《JAVA编程入门》的作者Daniel Liang关于编译的一段话:

用高级语言编写的程序称为源程序或源代码。因为计算机不能执行源程序，所以必须将源程序转换成机器代码才能执行。翻译可以使用另一种被称为解释器或编译器的编程工具来完成。”(Daniel Liang，“JAVA编程入门”，p8)。

.．.他仍在继续……