Int to bool is easy, just x != 0 will do the trick. To go the other way, since Go doesn’t support a ternary operator, you’d have to do: var x int if b { x = 1 } else { x = 0 } You could of course put this in a function: func … Read more
JAXB provides two ways to accomplish this: 1. Inline Schema Anntotations You can use JAXB schema annotations to control the class names. <xs:schema xmlns:xs=”http://www.w3.org/2001/XMLSchema” xmlns:jaxb=”http://java.sun.com/xml/ns/jaxb” jaxb:version=”2.1″> <xs:complexType name=”itemType”> <xs:annotation> <xs:appinfo> <jaxb:class name=”Item”/> </xs:appinfo> </xs:annotation> <xs:attribute name=”id” type=”xs:string” use=”required”/> </xs:complexType> </xs:schema> 2. External Binding File This customization can also be done via and external binding file: … Read more
As of Rust 1.32 you can use {to,from}_{ne,le,be}_bytes for integral types. let begin = 1234_i32; let bytes = begin.to_ne_bytes(); let and_back = i32::from_ne_bytes(bytes); For floating point you still have to rely on prior methods.
The way sum is defined, the return value is open-ended; more than one type can implement the trait Sum<i32>. Here’s an example where different types for a are used, both of which compile: #[derive(Clone, Copy)] struct Summer { s: isize, } impl Summer { fn pow(&self, p: isize) { println!(“pow({})”, p); } } impl std::iter::Sum<i32> … Read more
You can use the std::any::type_name function. This doesn’t need a nightly compiler or an external crate, and the results are quite correct: fn print_type_of<T>(_: &T) { println!(“{}”, std::any::type_name::<T>()) } fn main() { let s = “Hello”; let i = 42; print_type_of(&s); // &str print_type_of(&i); // i32 print_type_of(&main); // playground::main print_type_of(&print_type_of::<i32>); // playground::print_type_of<i32> print_type_of(&{ || “Hi!” … Read more
This is now touched on in the second edition of The Rust Programming Language. However, let’s dive in a bit in addition. Let us start with a simpler example. When is it appropriate to use a trait method? There are multiple ways to provide late binding: trait MyTrait { fn hello_word(&self) -> String; } Or: … Read more
2mantissa bits + 1 + 1 The +1 in the exponent (mantissa bits + 1) is because, if the mantissa contains abcdef… the number it represents is actually 1.abcdef… × 2^e, providing an extra implicit bit of precision. Therefore, the first integer that cannot be accurately represented and will be rounded is: For float, 16,777,217 … Read more
The biggest/largest integer that can be stored in a double without losing precision is the same as the largest possible value of a double. That is, DBL_MAX or approximately 1.8 × 10308 (if your double is an IEEE 754 64-bit double). It’s an integer. It’s represented exactly. What more do you want? Go on, ask me what … Read more