ARTS第六周

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Write a function that reverses a string. The input string is given as an array of characters char[].

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

You may assume all the characters consist of printable ascii characters.

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Given an input string, reverse the string word by word.

Note:
· A word is defined as a sequence of non-space characters.
· Input string may contain leading or trailing spaces. However, your reversed string should not contain leading or trailing spaces.
· You need to reduce multiple spaces between two words to a single space in the reversed string.

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Implement atoi which converts a string to an integer.

The function first discards as many whitespace characters as necessary until the first non-whitespace character is found. Then, starting from this character, takes an optional initial plus or minus sign followed by as many numerical digits as possible, and interprets them as a numerical value.

The string can contain additional characters after those that form the integral number, which are ignored and have no effect on the behavior of this function.

If the first sequence of non-whitespace characters in str is not a valid integral number, or if no such sequence exists because either str is empty or it contains only whitespace characters, no conversion is performed.

If no valid conversion could be performed, a zero value is returned.

Note:

· Only the space character ' ' is considered as whitespace character.
· Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. If the numerical value is out of the range of representable values, INT_MAX (231 − 1) or INT_MIN (−231) is returned.

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Implement int sqrt(int x).

Compute and return the square root of x, where x is guaranteed to be a non-negative integer.

Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.

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// file first.go
package main

import "fmt"

func Greeting() {
    fmt.Println("Hello FROM PLUGIN!!!")
}

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$ go build -buildmode=plugin -o first.so first.go

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// file main.go
package main

import (
    "fmt"
    "plugin"
)

func main() {
    plug, _ := plugin.Open("first.so")

    symbol, _ := plug.Lookup("Greeting")
    if symbol == nil {
        return
    }

    f := symbol.(func ())
    f()
}

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// second.go
package main

import "fmt"

type myPlugin string

func (p myPlugin) Greeting() {
    fmt.Println("Hello FROM PLUGIN!!!")
}

var MyPlugin myPlugin

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$ go build -buildmode=plugin -o second.so second.go

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package main

import (
    "fmt"
    "plugin"
)

type MyPlug interface {
    Greeting()
}

func main() {
    plug, _ := plugin.Open("second.so")

    symbol, _ := plug.Lookup("MyPlugin")

    var myPlugin MyPlug
    myPlugin, ok := symbol.(MyPlug)
    if !ok {
        // error handler
        return
    }

    myPlugin.Greeting()
}