literals

Given by a colleague as a puzzle, I cannot figure out how this C program actually compiles and runs. What is this >>>= operator and the strange 1P1 literal? I have tested in Clang and GCC. There are no warnings and the output is "???" #include <stdio.h> int main() { int a[2]={ 10, 1 }; while( a[ 0xFULL?'\0':-1:>>>=a<:!!0X.1P1 ] ) printf("?"); return 0; } Ilmari Karonen The line: while( a[ 0xFULL?'\0':-1:>>>=a<:!!0X.1P1 ] ) contains the digraphs :> and <: , which translate to ] and [ respectively, so it's equivalent to: while( a[ 0xFULL?'\0':-1 ] >>= a[ !!0X.1P1 ] ) The literal 0xFULL is the

Just reading some of the JS tuts on Mozilla and came across the statement "You should not use an object literal at the beginning of a statement. This will lead to an error or not behave as you expect, because the { will be interpreted as the beginning of a block." I don't understand what they mean. Could someone shed some light on this please An object literal starts with { { name: "Paul" age: 30 } // I wish But so does a block. { if (age < 30) console.log ("He's lying again"); } When the interpreter sees "{" it has to pick one interpretation (*). It picks "block" and tries to parse your

This question already has an answer here: Why is it legal to borrow a temporary? 3 answers Why isn't this rvalue promoted to an lvalue as specified in the reference? 1 answer I found that this is able to compile: let x = &mut 10; *x = 20; This is very confusing. What are the semantics of mutably borrowing an literal? I come from C++, where the compiler will definitely not allow me to refer to a rvalue like this: int *x = &10; int &y = 10; Like C++, Rust has the concept of rvalues and lvalue. The reference calls them value expressions (rvalue) and place expressions (lvalue). Additionally, there

Java's literal initializers are mostly used for primitives (e.g. int i = 2 and double j = 4.2 ), but there are certain non-primitive classes that also have literal initializers (e.g. String a = "Hello" or Number z = 43 ). I am looking to implement an initializer similar to that in a class that I wrote. I have a class Numeric that extends Number , that I would like to be able to initialize as Numeric a = 43 . Is there any way that this can be done in Java, and if so, how? Here is the part of the source code for Numeric public class Numeric extends Number { private HashMap<Primitive, Number>

I stumbled upon this function in an answer to this question : /* Note: I've formatted the code for readability. */ const char * getString() { const char *x = "abcstring"; return x; } I was surprised to discover that returning a pointer to the literal string worked, and didn't segfault like I thought it would. I always assumed that literals were pushed on to the stack or put in some other temporary memory, but where limited to the scope of the function. But here it seems that they are more static than I had imagined. Are they then put into something sort of string pool that's global to the