letx;foobar(x);// error: borrow of possibly-uninitialized variable: `x` x = 42; 然而,这样做完全没问题: 代码语言:javascript 复制 letx;x=42;foobar(x);// the type of `x` will be inferred from here 下划线表示特殊的命名,或者更确切地说是「缺失的命名」,它和 Python 的用法有点像: 代码...
hir::TyKind::Infer=>{// Infer also appears as the type of arguments or return// values in an ExprKind::Closure, or as// the type of local variables. Both of these cases are// handled specially and will not descend into this routine.self.ty_infer(None,ast_ty.span)}// impl AstCon...
thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 10', src/main.rs:19:19 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace 什么情况下会有这种错误? 当下标是一个变量比如从stdin中获取的,这时就会有可能有问题,而且这个问题并不能在...
union:声明一个联合体 type:为存在类型定义一个别名 let:定义变量(Bind a value to a variable) 除了上述关键字可以自定义一些具体的类型之外,Rust还支持如下基础类型: array:[T; N] bool:布尔类型 char:a single character,占四个字节,unicode f32/f63:32bit浮点、64bit浮点 fn:函数指针类型 i8/i16/i32/...
let variable_name:dataType=value; //指定类型 1. 2. 命名示例 fn main() { let fees=25_000; let salary:f64=35_000.00; println!("fees is {} and salary is {}",fees,salary); } 1. 2. 3. 4. 5. 上面代码的输出为 费用为25000,薪水为35000 。
thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 10', src/main.rs:19:19 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace 程序在索引操作中使用一个无效的值时导致 运行时 错误。程序带着错误信息退出,并且没有执行最后的 println!
The type of the variablepadovanisstd::vec::Vec<i32>, a vector of 32-bit integers. In memory, the final value ofpadovanwill look something likeFigure 4-2. Figure 4-2.A Vec<i32> on the stack, pointing to its buffer in the heap ...
encountered type variable --> /tmp/icemaker_global_tempdir.qRMnYYI19Q4z/rustc_testrunner_tmpdir_reporting.nQT3i3c5eog1/mvce.rs:8:10 | 8 | baz(|x| ()); | ^ | note: delayed at compiler/rustc_hir_typeck/src/expr_use_visitor.rs:174:20 - disabled backtrace --> /tmp/icemaker_...
("{} - type: {}", num3, get_type(&num3));// max values// std is the standard library/crate,// it gives access to a rich variety of features,// here we use the type modules (i32, i16, etc.) and propertieslet max_i32 = std::i32::MAX;let max_i16 = std::i16::MAX;...
Type safe: The compiler assures that no operation will be applied to a variable of a wrong type. Memory safe: Rust pointers (known as references) always refer to valid memory. Data race free: Rust's borrow checker guarantees thread-safety by ensuring that multiple parts of a program can't...