main

问题 There are a lot of similar questions, but none for this specifically. I have a Netbeans project with a bunch of packages. Only one has Main. I'd like to be able to create a .jar from just one of the packages (and all the classes it contains, of course), which doesn't have main. Is this feasible without having to put that package in another project or without having to screw around with build.xml? If the latter, any easy way or good rtfm links? The point is i'm developing part of an

问题 I know it's legal to have a main method in an abstract class, because Eclipse allows me to do the following and run the class as a java application. But does it make sense to do something like this? Is there a real world scenario where one would need to have a main method in an abstract class? public abstract class Automobile { public Boolean powerOn() { // generic implementation for powering on an automobile return true; } public void move() { // generic implementation for move } public void

问题 I would like to execute an executable file whose main() returns 2 using system() . This is what I did #include <stdio.h> #include <string.h> int main(int argc, char *agrv[]) { char command[7]; strcpy(command, "./test1"); printf("The return value: %d\n", system(command)); return 0; } and test1 is #include <stdio.h> int main(void) { printf("test1 has been executed and its return value is 2\n"); return 2; } This is what I'm getting test1 has been executed and its return value is 2 The return

问题 Hey I am new to spring and am trying to run multiple run methods in the main in my Applications.java. import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.boot.SpringApplication; import org.springframework.context.annotation.ComponentScan; @ComponentScan @EnableAutoConfiguration public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); SpringApplication.run(ScheduledTasks.class); } } When I

问题 This question already has answers here : When can argv[0] have null? (4 answers) Closed 2 years ago . In the data structures class that I am currently taking, we have been tasked with writing a web crawler in C++. To give us a head start, the professor provided us with a program to get the source from a given URL and a simple HTML parser to strip the tags out. The main function for this program accepts arguments and so uses argc/argv. The code used to check for the arguments is as follows: //

问题 I learned from chapter 9 of Learn You A Haskell For Great Good that By convention, we don't usually specify a type declaration for main . As far as I can tell, this convention is widespread. However, if I compile, using the -Wall flag, a program that lacks a type signature for main , such as -- test.hs -- main :: IO () main = print (1 :: Int) GHC does issue a warning: $ ghc -Wall test.hs [1 of 1] Compiling Main ( test.hs, test.o ) test.hs:2:1: Warning: Top-level binding with no type signature

问题 I was trying to create a program that takes arguments by command line, using main() function arguments. As a (basic) C++ programmer (even if I know quite well pointers and array in C-style) I hardly ever used char* strings and C-arrays. I spent some to take main() arguments and transform it in std::string ... So asked myself: why in C++ the main() function is not overloaded to take an std::vector<std::string> argv instead of the old char* argv[] ? For "overload" I mean the coexistence of main

问题 So I just tried excluding String[] args from the main method It compiled alright ! But JVM is showing an exception Why did it compile when String[] args HAS to be included every time ? What is going on here ? Why won't it show a compilation error ? typing this made me think that may be compiler did not see it as THE main method ..is that so ? If that is the case..why not ? I mean isn't there supposed to be just one main method that MUST have String[] args as the argument ? 回答1: typing this

问题 Can anyone tell me the use of making main method as final in java. while this is allowed in java public static final void main(String[] args) { } I dont see any use of making it final. anyways it is static so we can not override it. 回答1: Adding final to a static method can actually make a difference. Consider the following code: class A { public static void main(String[] args) { System.out.println("A"); } } class B extends A { public static void main(String[] args) { System.out.println("B");

问题 Why we put main() method always inside the class in C# while in c++ it always placed outside of the class . 回答1: For historical reasons. C++ evolved from C, which had a global main() function. C# is much younger and was designed from scratch. One of the design features of C# is the absence of global functions, so the main function has to belong to a class. 回答2: The C++ language designers followed the lead of C and so the main function is a plain function. The C# language designers made the