main

I noticed that the main.cpp in a Qt application has to contain the following line: QApplication app(argc, argv); I know that argc is the number of command-line arguments, and argv is that array list of command-line arguments. But, the question in my mind is: what are those arguments I'm passing to the constructor and at the same time cannot explicitly see? What is working behind the scences out there? Thanks. There are no hidden arguments. You can explicitly see every argument- argc, argv . There's nothing in that line of code that's behind the scenes. From looking at your comments to other

In java we always write: public static void main(String[] args){...} when we want to start writing a program. My question is, is it the same for Haskell, IE: can I always be sure to declare: main = do, when I want to write code for a program in Haskell? for example: main = do putStrLn "What's your name?" name <- getLine putStrLn ("Hello " ++ name) This program is going to ask the user "What's your name?" the user input will then be stored inside of the name-variable, and "Hello" ++ name will be displayed before the program terminates. Short answer : No , we have to declare a main = , but not a

Possible Duplicate: main() in C, C++, Java, C# I'm new to programming in general, and C in particular. Every example I've looked at has a "main" function - is this pre-defined in some way, such that the name takes on a special meaning to the compiler or runtime... or is it merely a common idiom among C programmers (like using "foo" and "bar" for arbitrary variable names). No, you need to define main in your program. Since it's called from the run-time, however, the interface your main must provide is pre-defined (must return an int , must take either zero arguments or two, the first an int ,

How would you run a command and pass some custom arguments with Flutter/Dart so they can then be accessed in the main() call such as: flutter run -device [my custom arg] So then I can access it with: void main(List<String> args) { print(args.toString()); } Thank you. There is no way to do that, because when you start an app on your device there are also no parameters that are passed. If this is for development, you can pass -t lib/my_alternate_main.dart to flutter run to easily switch between different settings where each alternate entry-point file calls the same application code with

I know that main() can be overloaded in a class with the compiler always taking the one with String[] args as arguments as the main method from where the execution starts. But is it possible to declare the same main(String args[]) in an interface and implement it in different classes differently? For example, package test; interface test { public void main(String args[]); public void display(); } package test; class Testclass1 implements test { public void display() { System.out.println("hello"); } public static void main(String[] args) { test t; t.display(); } } package temp; import test.*;

IntelliJ IDEA 10.5 (probably this matters). I am new to Scala, so I started in an akward way. I created one file with two classes -- empty MainApp and another class, HelloWorld with method main. I compiled it and executed -- IntelliJ automatically detected HelloWorld as main class. It was OK. Then, I moved main method to MainApp, and deleted (then empty) HelloWorld class. When I tried to run it, IntelliJ sticked to HelloWorld nevertheless. So I reconfigured project and selected MainApp as main class. I tried to run it with such result: MainApp main method should be static I am completely

I'm learning C# and I'm very new to it, so forgive me for the seemingly stupid question. I have some experience in Java, and I noticed that C# programs also need a main() method in their main class. What if I want to create a class that isn't a main class, i.e. one that I import into a main class? I tried to do that, and when I compile (via cmd using csc File.cs ) the compiler says that the .exe that it will make has no main() method. Does that mean that I was wrong, and every class needs a main() method, or that I'm compiling it wrongly? Maybe the problem's in the code (since I'm relying on