string与StringBuilder之性能比较

知道“StringBuilder比string性能强”好多年了，近日无聊病发作，就把这两个家伙给动了手术：

using System;

using System.Text;

namespace ConsoleApplication1

{

    classProgram

    {

        staticvoid Main(string[] args)

        {

            int start = Environment.TickCount;    //计时打点

            fun1();

            int middle = Environment.TickCount;  //计时打点

            fun2();

            int end = Environment.TickCount;  //计时打点

            Console.WriteLine("string         运行时间 {0} 秒", 0.001 * (middle - start));

            Console.WriteLine("StringBuilder  运行时间 {0} 秒", 0.001 * (end - middle));

            Console.ReadKey();

        }

       

        //fun1和fun2是两个结构功能相同的无聊耗时方法

        privatestaticvoid fun1()

        {

            for (int i = 0; i < 1000; i++)

            {

                string s = "";     

                for (int j = 0; j < 200; j++)

                {

                    s += "Outer index = ";

                    s += i;

                    s += " Inner index = ";

                    s += j;

                    s += " ";

                }

            }

        }

 

        privatestaticvoid fun2()

        {

            for (int i = 0; i < 1000; i++)

            {

                StringBuilder s = newStringBuilder();

                for (int j = 0; j < 200; j++)

                {

                    s.Append("Outer index = ");

                    s.Append(i);

                    s.Append("Inner index = ");

                    s.Append(j);

                    s.Append(" ");

                }

            }

        }

    }

}

可见区别之大。

用vs自带的性能分析工具分析如下（过程比较慢）：

查看函数详细信息：

可见fun1明显比fun2的非独占分配数大，如果想进一步了解细节，可点击相应区域，结果如下

 接下去，你懂得。。。

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