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“Could not find the main class: XX. Program will exit.”

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问题 I have managed to run my jar file with a command prompt, but its always giving me a reponse of Could not find the main class: XX. Program will exit. Please help me out, thanks. 回答1: See Setting an Application's Entry Point If you have an application bundled in a JAR file, you need some way to indicate which class within the JAR file is your application's entry point. You provide this information with the Main-Class header in the manifest, which has the general form: Main-Class: classname The

Main Menu In Swift

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I would like to create a main menu for my game in swift. I am using the following code: import SpriteKit class menuScene: SKScene { //Adding Start Button let startButton = SKSpriteNode(imageNamed: "playButton") override func didMove(to view: SKView) { //Temporary Background backgroundColor = SKColor.darkGray //Start Button startButton.position = CGPoint(x: size.width / 2, y: size.height / 2) addChild(startButton) } override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { for touch in touches { let location = touch.location(in: self); //Finding location of touch if atPoint

Is there any reason to modify the main.m file in your iOS applications?

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问题 I'm trying to get a better understanding of the purpose of each file contained in a basic iOS application. Is there any reason to modify the main.m file? I'm wondering if that file ever needs to be touched. If you do modify it, why? 回答1: In 99.9% of all cases, there is no need to touch main.m . In the other 0.1%, you might want to change the arguments of the call to the UIApplicationMain() function. The last two arguments of this function specify the names of the classes that represent your

Why calling main() is not allowed in C++

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C++03 3.6.1.3 : The function main shall not be used (3.2) within a program. ... I wonder why this rule exists... Is anyone aware of any system/implementation where it would be a problem if main were used? P.S. 1. I know the definition of the term used . 2. I know there are simple workarounds like calling a single MyMain() from main() and using MyMain() instead. 3. The question is about real-world implementations which would have a problem if the restriction weren't there. Thanks! In addition to the other answers: The c++ spec guarantees that all static initialization has happened before main

Number of executed Instructions different for Hello World program Nasm Assembly and C

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I have a simple debugger (using ptrace : http://pastebin.com/D0um3bUi ) to count the number of instructions executed for a given input executable program. It uses ptrace single step execution mode to count instructions. For that when the program 1)'s executable (a.out from gcc main.c) is given as input to my test debuggger it prints around 100k as instructions executed. When I use -static option it gives 10681 instructions. Now in 2) I create an assembly program and use NASM for compiling and linking and then when this executable is given as test debuggers input it is showing 8 instructions as

Legal definitions of main() in C++14

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问题 The last draft of C++14 that I was able to find says, regarding main() [3.6.1]: An implementation shall not predefine the main function. This function shall not be overloaded. It shall have a return type of type int, but otherwise its type is implementation-defined. All implementations shall allow both — a function of () returning int and — a function of (int, pointer to pointer to char) returning int and (paragraph 5) If control reaches the end of main without encountering a return statement

Why do applets not need a main()?

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This applies to subclasses of Applet, Servlet, Midlet, etc. Why do they not need a main() ? If I wanted to create a Craplet class that starts at init() or something similar, is it bad design, or how would I go about doing it? ojblass It is actually good design but not obvious and what you want to do would have no effect so it is a little counter intuitive. These types of applications live their lives in containers and as such their entry points are determined by the standards those containers must adhere to. The designers of these standards chose not to call the entry point main. You would

calling another method from the main method in java [duplicate]

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问题 This question already has an answer here: calling non-static method in static method in Java [duplicate] 14 answers I have class foo{ public static void main(String[] args){ do(); } public void do(){} } but then when I call do() from main by running the command java foo on the command line, java complains that you can't call a method from a static function. So my question is: How do you call methods from the main method and if it is not possible what are some alternative strategies to call

Why does const int main = 195 result in a working program but without the const it ends in a segmentation fault?

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问题 Consider following C program (see live demo here). const int main = 195; I know that in the real world no programmer writes code like this, because it serves no useful purpose and doesn't make any sense. But when I remove the const keyword from above the program it immediately results in a segmentation fault. Why? I am eager to know the reason behind this. GCC 4.8.2 gives following warning when compiling it. warning: 'main' is usually a function [-Wmain] const int main = 195; ^ Why does the

How can I write a Windows application without using WinMain?

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问题 Windows GUI applications written in C/C++ have 'WinMain' as an entry point (rather than 'main'). My understanding of this is that the compiler generates a 'main' function to be called by the C Runtime. This 'main' function sets up the necessary environment for the GUI and calls into 'WinMain' (specifying the instance handles etc.). In short, I believe console and GUI application startup to differ in the following way: Console application: C Runtime --> 'main' function (hand-coded) GUI