println

问题 I often find myself doing things like: println(foo) when I'd like to do: println foo The compiler does not allow this. Also, println is a mouthful, I really just want to say: echo foo So, in a base package object I created the echo version of println: def echo(x: Any) = Console.println(x) Easy enough, have echo application wide, great. Now, how do I invoke echo without needing to wrap the Any to print in parens? 回答1: object ∊ {def cho(s: Any) {println(s)}} ∊cho "Hello world" will save your

问题 I am working on an Swift app with Core Data. I created my *.xcdatamodeld file and created a NSManagedObject Subclass ( Editor -> Create NSManagedObject Subclass... ). Everything works fine except when I try to println an instantiated object of that class (lets call it Person ) the console prints blank or simply Optional() if not unwrapped. I tried adding DebugPrintable or Printable via class extension without success. Is this a known limitation of CoreData objects? What am I missing? Adding

问题 I have a server-client program set that I'm working on and right now I'm having problems with the protocol because the new line at the end of the println statement is confusing the metadata. In other words, I need to print to a PrintWriter without the new line at the end. I tried just print, but for some reason the other program doesn't get the message that way. I tried, for the sake of experimentation, adding "\n", "\r", and "\n\r" to the end of the statement and it still didn't get any data

问题 I am new to Java programming, and today while messing with eclim and vim, I discovered that the System.out.println(); function is not working. class apples{ public static void main(String args[]){ double tuna = 5.28; System.out.print(tuna); } } This does not give me a result. But when I do: class apples{ public static void main(String args[]){ double tuna = 5.28; System.out.println(tuna); } } (The only difference is the "println") I get 5.28, the correct behavior. Anyone know why this would

问题 In Go, if we want to print something, we can do so as follows: import "fmt" func main(){ fmt.Println("Hello world!") } But I found that one can do the same without importing fmt : func main(){ println("Hello world!") } Could someone please explain? 回答1: println is an built-in function (into the runtime) which may eventually be removed, while the fmt package is in the standard library, which will persist. See the spec on that topic. For language developers it is handy to have a println without

问题 Can you tell me how to increase the size of the font using System.out.println in java. 回答1: There is no concept of "font" with System.out . Edit the console font settings for whatever application you're using as an output console. 回答2: You cannot do this through coding as in the font size is based on your console. I assumed you use eclipse to code your java code. So, you can change eclipse console font size here. General > Appearance > Colors and Fonts Which you can get the source here. http:

问题 What does my own made class need to support in order for println() to print it? For example, I have: public class A { ... } What methods should class A have to make this code work? Maybe something like this: public static void main() { A a = new A(); System.out.println(a); } I have a guess that the toString() method must be overloaded. Am I right? Is this enough? 回答1: You can print any Object using System.out.println(Object). This overloaded version of println will print out toString

问题 In Rust, this works: fn main() { let a = [0; 32]; println!("{:?}", a); } but this doesn't: fn main() { let a = [0; 33]; println!("{:?}", a); } Compile error: error[E0277]: the trait bound `[{integer}; 33]: std::fmt::Debug` is not satisfied --> src/main.rs:3:22 | 3 | println!("{:?}", a); | ^ the trait `std::fmt::Debug` is not implemented for `[{integer}; 33]` | = note: `[{integer}; 33]` cannot be formatted using `:?`; if it is defined in your crate, add `#[derive(Debug)]` or manually implement

问题 class test{ public static void main(String args[]){ int a = 011; System.out.println(a); } } Why I am getting 9 as output instead of 011 ? How can I get 011 as output? 回答1: The JLS 3.10.1 describes 4 ways to define integers. An integer literal may be expressed in decimal (base 10), hexadecimal (base 16), octal (base 8), or binary (base 2). An octal numeral consists of a digit 0 followed by one or more of the digits 0 through 7 ... A decimal numeral is either the single digit 0, representing

问题 I have a have a class that has a method which takes a string. Then I have a method which returns the value of the above method. When ever I get the return value in my main class and print it the printed value is "ExamQuestion@143c8b3". How do I get it to print correctly? Thanks 回答1: Whenever you get the format "@" this is the default format of an object's toString() method. Calling System.out.println(question); calls ExamQuestion.toString() . If the method isn't overridden, the version in the