本文中的5種開發(fā)語言為：（以下排名不分先后，只是提筆寫的）

• C#
• Python
• C++
• Go
• Java

本文計(jì)算指定一個(gè)數(shù)targetNum，我們計(jì)算一下從1到targetNum中的素?cái)?shù)，并輸出。

1. 本文在同一臺(tái)虛擬機(jī)中運(yùn)行計(jì)算

2. 各語言實(shí)現(xiàn)

2.1. C#語言

2.1.1. 開發(fā)環(huán)境

1. VS2019
2. .Net5.0

2.1.2. 代碼

using System;using System.Diagnostics;namespace CSharpPrimeNumber{    class Program    {        static void Main(string[] args)        {            PrimeNumber(100);            PrimeNumber(200);            PrimeNumber(500);            PrimeNumber(1000);            PrimeNumber(2000);            PrimeNumber(5000);            PrimeNumber(10000);            PrimeNumber(50000);            PrimeNumber(100000);            Console.ReadKey();        }        private static void PrimeNumber(int targetNum)        {            Stopwatch sw = new Stopwatch();            sw.Start();            for (int i = 2; i < targetNum; i++)            {                int halfNum = i / 2;                bool isPrimeNumber = true;                for (int j = 2; j < halfNum; j++)                {                    if (i % j == 0)                    {                        isPrimeNumber = false;                        break;                    }                }                if (isPrimeNumber)                {                    //Console.WriteLine($"數(shù){i}是素?cái)?shù)...");                }            }            sw.Stop();            TimeSpan ts2 = sw.Elapsed;            Console.WriteLine($"{targetNum}:素?cái)?shù)計(jì)算總共花費(fèi){ts2.TotalSeconds}s.");        }    }}

2.1.2. 執(zhí)行結(jié)果

以下編譯為Release并點(diǎn)擊可執(zhí)行程序運(yùn)行

2.2 Python

2.2.1. 開發(fā)環(huán)境

1. VSCode
2. python 3.9.7

2.2.2. 代碼

from time import *def primeNum(targetNum):    begin_time = time()    for i in range(2,targetNum):        halfNum=i/2        isPrimeNumber = True        j=2        while j <= halfNum:            if i%j==0:                isPrimeNumber=False                break            j=j+1        # if isPrimeNumber:        #     # print(str(i)+"數(shù)是素?cái)?shù)")        end_time = time()    run_time = end_time-begin_time    print ("{}:素?cái)?shù)計(jì)算總共耗時(shí):{}s".format(targetNum,run_time)) primeNum(100)primeNum(200)primeNum(500)primeNum(1000)primeNum(2000)primeNum(5000)primeNum(10000)primeNum(50000)primeNum(100000)

2.2.2. 執(zhí)行結(jié)果

以下使用命令行執(zhí)行

2.3. C++

2.3.1. 開發(fā)環(huán)境

1. VS2019

2.3.2. 代碼

using namespace std;void primeNum(int targetNum){    clock_t startTime = clock();    int numCount = 0;    for (int i = 2; i < targetNum; i++)    {        int halfNum = i / 2;        bool isPrimeNumber = true;        for (int j = 2; j <= halfNum; j++)        {            if (i % j == 0)            {                isPrimeNumber = false;                break;            }        }        if (isPrimeNumber)        {            numCount++;            //cout << "數(shù)" << i << "是素?cái)?shù)..." << endl;        }    }    clock_t endTime = clock();    cout << targetNum << ":素?cái)?shù)計(jì)算總共花費(fèi)" << endTime - startTime<<" ms ,素?cái)?shù)個(gè)數(shù)為："<< numCount << endl;}int main(){	primeNum(100);	primeNum(200);	primeNum(500);	primeNum(1000);	primeNum(2000);	primeNum(5000);	primeNum(10000);	primeNum(50000);    primeNum(100000);}

2.3.3. 執(zhí)行結(jié)果

2.4. Go

2.4.1. 開發(fā)環(huán)境

1. go version go1.17.2 windows/amd64
2. VS Code

2.4.2. 代碼

package mainimport(	"fmt"	"time")func main()  {	primeNum(100)	primeNum(200)	primeNum(500)	primeNum(1000)	primeNum(2000)	primeNum(5000)	primeNum(10000)	primeNum(50000)	primeNum(100000)}func primeNum(targetNum int){	startTime := time.Now()	var halfNum int	var isPrimeNumber bool	var numCount int	halfNum=targetNum	numCount=0	for i := 2; i <= targetNum; i++ {        halfNum=i/2		isPrimeNumber = true		for j := 2; j <= halfNum; j++ {			if i%j ==0{				isPrimeNumber=false				break			}		}		        if isPrimeNumber{			numCount=numCount+1            // fmt.Printf("%v數(shù)是素?cái)?shù)/n",i)		}	}		elapsedTime := time.Since(startTime) / time.Millisecond 	fmt.Printf("%v:素?cái)?shù)計(jì)算總共耗時(shí):%d ms ,素?cái)?shù)個(gè)數(shù)為：%v/n",targetNum, elapsedTime,numCount)}

2.4.3. 執(zhí)行結(jié)果

2.5. Java

2.5.1. 開發(fā)環(huán)境

1. Java8
2. Idea

2.5.2. 代碼

    public static void main(String[] args) {        PrimeNumber(100);        PrimeNumber(200);        PrimeNumber(500);        PrimeNumber(1000);        PrimeNumber(2000);        PrimeNumber(5000);        PrimeNumber(10000);        PrimeNumber(50000);        PrimeNumber(100000);    }    private static void PrimeNumber(int targetNum)    {        long startTime=System.currentTimeMillis();   //獲取開始時(shí)間        int numCount = 0;        for (int i = 2; i < targetNum; i++)        {            int halfNum = i / 2;            boolean isPrimeNumber = true;            for (int j = 2; j <= halfNum; j++)            {                if (i % j == 0)                {                    isPrimeNumber = false;                    break;                }            }            if (isPrimeNumber)            {                numCount++;//                System.out.println(String.format("數(shù)%s是素?cái)?shù)...",i));            }        }        //函數(shù)主體代碼        long endTime=System.currentTimeMillis(); //獲取結(jié)束時(shí)間        System.out.println(String.format("%s:素?cái)?shù)計(jì)算總共花費(fèi)%s ms,素?cái)?shù)個(gè)數(shù)為：%s",targetNum,(endTime-startTime),numCount));    }}

2.5.3. 執(zhí)行結(jié)果

3. 效率折線

1. C++ 最快
2. Java和C#在這個(gè)上沒有太大的區(qū)別（沒有考慮預(yù)熱）
3. GO表現(xiàn)并沒有很快(沒有使用協(xié)程)
4. Python最慢