将数组移位k的函数语法错误 [英] Syntax error in function to shift array by k

问题描述

我正尝试将数组k向左移动. 这是我的代码.但是我在shifted;;行上遇到了编译错误.

I'm trying to shift array by k to left. Here's my code. But I'm getting compile error on shifted;; line.

let shift_left (arr: array) (kk: int) =
    let size = Array.length arr in
        let k = kk mod size in
    let shifted = Array.make size 0 in

    for i = 0 to size - 1 do
        if i < k
        then (shifted.(size - k + i) <- arr.(i))
        else (shifted.(i-k) <- arr.(i))
    done

    shifted;;


let arr = [| 1; 2; 3; 4; 5; 6; 7; 8; 9; 10 |];;
let shifted = shift arr 4;;

Array.iter print_int arr;
print_string "\n";;

Array.iter print_int shifted;
print_string "\n";;

这是我进入终端的内容:

Here is what I getting in terminal:

$ ocamlc -o shift shift.ml

File "shift.ml", line 11, characters 1-8:
Error: Syntax error

推荐答案

此处有两个编译器错误:

There are two compiler errors here:

1. done和shifted之间的语法错误.由于换行符在OCaml中不重要，因此将其解析为done shifted;;，它看起来像函数应用程序，但由于done是关键字而不是可能引用函数的标识符，因此无效.使用序列运算符;可以按顺序求值两个表达式.

1. A syntax error between done and shifted. Because line breaks are not significant in OCaml, it will be parsed as done shifted;;, which looks like a function application, but is not valid since done is a keyword, not an identifier that might refer to a function. Use the sequence operator, ;, to evaluate two expressions in sequence.

类型错误:array不是具体类型，它使用一个类型参数来指定其包含的值的类型.在这种情况下，它应该是int array.

A type error: array is not a concrete type, it takes a type parameter specifying the type of value it contains. It should be int array in this case.

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