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< ol class = "chapter" > < li class = "chapter-item expanded " > < a href = "../intro.html" > < strong aria-hidden = "true" > 1.< / strong > Introduction< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/index.html" > < strong aria-hidden = "true" > 2.< / strong > Idioms< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "../idioms/coercion-arguments.html" > < strong aria-hidden = "true" > 2.1.< / strong > Use borrowed types for arguments< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/concat-format.html" > < strong aria-hidden = "true" > 2.2.< / strong > Concatenating Strings with format!< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/ctor.html" class = "active" > < strong aria-hidden = "true" > 2.3.< / strong > Constructor< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/default.html" > < strong aria-hidden = "true" > 2.4.< / strong > The Default Trait< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/deref.html" > < strong aria-hidden = "true" > 2.5.< / strong > Collections Are Smart Pointers< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/dtor-finally.html" > < strong aria-hidden = "true" > 2.6.< / strong > Finalisation in Destructors< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/mem-replace.html" > < strong aria-hidden = "true" > 2.7.< / strong > mem::{take(), replace()}< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/on-stack-dyn-dispatch.html" > < strong aria-hidden = "true" > 2.8.< / strong > On-Stack Dynamic Dispatch< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/ffi/intro.html" > < strong aria-hidden = "true" > 2.9.< / strong > Foreign function interface (FFI)< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "../idioms/ffi/errors.html" > < strong aria-hidden = "true" > 2.9.1.< / strong > Idiomatic Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/ffi/accepting-strings.html" > < strong aria-hidden = "true" > 2.9.2.< / strong > Accepting Strings< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/ffi/passing-strings.html" > < strong aria-hidden = "true" > 2.9.3.< / strong > Passing Strings< / a > < / li > < / ol > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/option-iter.html" > < strong aria-hidden = "true" > 2.10.< / strong > Iterating over an Option< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/pass-var-to-closure.html" > < strong aria-hidden = "true" > 2.11.< / strong > Pass Variables to Closure< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/priv-extend.html" > < strong aria-hidden = "true" > 2.12.< / strong > Privacy For Extensibility< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/rustdoc-init.html" > < strong aria-hidden = "true" > 2.13.< / strong > Easy doc initialization< / a > < / li > < li class = "chapter-item expanded " > < a href = "../idioms/temporary-mutability.html" > < strong aria-hidden = "true" > 2.14.< / strong > Temporary mutability< / a > < / li > < / ol > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/index.html" > < strong aria-hidden = "true" > 3.< / strong > Design Patterns< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/intro.html" > < strong aria-hidden = "true" > 3.1.< / strong > Behavioural< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/command.html" > < strong aria-hidden = "true" > 3.1.1.< / strong > Command< / a > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/interpreter.html" > < strong aria-hidden = "true" > 3.1.2.< / strong > Interpreter< / a > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/newtype.html" > < strong aria-hidden = "true" > 3.1.3.< / strong > Newtype< / a > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/RAII.html" > < strong aria-hidden = "true" > 3.1.4.< / strong > RAII Guards< / a > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/strategy.html" > < strong aria-hidden = "true" > 3.1.5.< / strong > Strategy< / a > < / li > < li class = "chapter-item expanded " > < a href = "../patterns/behavioural/visitor.html" > < strong aria-hidden = "true" > 3.1.6.< / strong > Visitor< / a > < / li > < / ol > < / li > < li class = "chapter-item expanded
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< h1 id = "constructors" > < a class = "header" href = "#constructors" > Constructors< / a > < / h1 >
< h2 id = "description" > < a class = "header" href = "#description" > Description< / a > < / h2 >
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< p > Rust does not have constructors as a language construct. Instead, the
convention is to use a static < code > new< / code > method to create an object.< / p >
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< h2 id = "example" > < a class = "header" href = "#example" > Example< / a > < / h2 >
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< pre > < code class = "language-rust ignore" > // A Rust vector, see liballoc/vec.rs
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pub struct Vec< T> {
buf: RawVec< T> ,
len: usize,
}
impl< T> Vec< T> {
// Constructs a new, empty `Vec< T> `.
// Note this is a static method - no self.
// This constructor doesn't take any arguments, but some might in order to
// properly initialise an object
pub fn new() -> Vec< T> {
// Create a new Vec with fields properly initialised.
Vec {
// Note that here we are calling RawVec's constructor.
buf: RawVec::new(),
len: 0,
}
}
}
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< / code > < / pre >
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< h2 id = "see-also" > < a class = "header" href = "#see-also" > See also< / a > < / h2 >
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< p > The < a href = "../patterns/creational/builder.html" > builder pattern< / a > for constructing objects
where there are multiple configurations.< / p >
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