reference

问题 What is the purpose of & in the code &i in list ? If I remove the & , it produces an error in largest = i , since they have mismatched types (where i is &32 and i is i32 ). But how does &i convert i into i32 ? fn largest(list: &[i32]) -> i32 { println!("{:?}", list); let mut largest = list[0]; for &i in list { if i > largest { largest = i; } } largest } fn main() { let hey = vec![1, 3, 2, 6, 90, 67, 788, 12, 34, 54, 32]; println!("The largest number is: {}", largest(&hey)); } Playground It

问题 What is the purpose of & in the code &i in list ? If I remove the & , it produces an error in largest = i , since they have mismatched types (where i is &32 and i is i32 ). But how does &i convert i into i32 ? fn largest(list: &[i32]) -> i32 { println!("{:?}", list); let mut largest = list[0]; for &i in list { if i > largest { largest = i; } } largest } fn main() { let hey = vec![1, 3, 2, 6, 90, 67, 788, 12, 34, 54, 32]; println!("The largest number is: {}", largest(&hey)); } Playground It

问题 What is the purpose of & in the code &i in list ? If I remove the & , it produces an error in largest = i , since they have mismatched types (where i is &32 and i is i32 ). But how does &i convert i into i32 ? fn largest(list: &[i32]) -> i32 { println!("{:?}", list); let mut largest = list[0]; for &i in list { if i > largest { largest = i; } } largest } fn main() { let hey = vec![1, 3, 2, 6, 90, 67, 788, 12, 34, 54, 32]; println!("The largest number is: {}", largest(&hey)); } Playground It

问题 When I add a .dll file as a reference in C# application it shows an error : A reference to the "....dll" could not be added.Please make sure that the file is accessible and that it is a valid assembly or COM component. ILDissassembler says there is no valid CLR header so I try to register it using regsvr32 and that gives me another error: The module "" was loaded but the call to DLLRegisterServer failed with error code '0x80004005' I am using VS2010 ultimate version on a 64bit Windows 7

问题 Say I have the following structure: package require Itcl itcl::class AAA { private variable m_list {} constructor {} { fill m_list list } } How to get a reference on the m_list in order to write foreach elem $reference {.......} Consider that list is really big and I don't want to copy it! 回答1: Tcl variables use copy-on-write semantics. You can safely pass a value around, assigning multiple variables to it, without worrying about it taking up more space in memory. For example set x {some list

问题 Even though "String" is a reference type, in VB.NET, we only get the effect of using of a reference type if we pass a parameter as ByRef. So, unlike C# even reference types in VB.NET behaves like value type by default. Why is there this kind of difference? 回答1: If you are trying to understand reference types and value types and their differences in VB.NET and C#.NET using string as an example then you will confuse yourself big time. Just as David mentioned, strings are reference types, but

问题 Even though "String" is a reference type, in VB.NET, we only get the effect of using of a reference type if we pass a parameter as ByRef. So, unlike C# even reference types in VB.NET behaves like value type by default. Why is there this kind of difference? 回答1: If you are trying to understand reference types and value types and their differences in VB.NET and C#.NET using string as an example then you will confuse yourself big time. Just as David mentioned, strings are reference types, but

问题 Sometimes I have a struct containing a value which is wrapped in a RefCell , and I want to borrow the value, but I don't want to make the signature of the accessor function to depend on the internal implementation. To make it work, I need to return the reference as a Ref<T> instead of a &T . For example, if this is my struct: use std::cell::RefCell; pub struct Outer<T> { inner: RefCell<T>, } I could write an accessor like this: use std::cell::Ref; impl<T> Outer<T> { fn get_inner_ref(&self) ->

问题 Sometimes I have a struct containing a value which is wrapped in a RefCell , and I want to borrow the value, but I don't want to make the signature of the accessor function to depend on the internal implementation. To make it work, I need to return the reference as a Ref<T> instead of a &T . For example, if this is my struct: use std::cell::RefCell; pub struct Outer<T> { inner: RefCell<T>, } I could write an accessor like this: use std::cell::Ref; impl<T> Outer<T> { fn get_inner_ref(&self) ->

问题 Sometimes I have a struct containing a value which is wrapped in a RefCell , and I want to borrow the value, but I don't want to make the signature of the accessor function to depend on the internal implementation. To make it work, I need to return the reference as a Ref<T> instead of a &T . For example, if this is my struct: use std::cell::RefCell; pub struct Outer<T> { inner: RefCell<T>, } I could write an accessor like this: use std::cell::Ref; impl<T> Outer<T> { fn get_inner_ref(&self) ->