猜猜几种c#字符串连接所消耗时间的先后?

猜猜几种c#字符串连接所消耗时间的先后?1. 字符串字面值直接连加

test = "I1" + "I2" + "I3" + "I4" + "I5";

2.字符串字面值用+=相加

test = "I6";
test += "I7";
test += "I8";
test += "I9";
test += "I10";

3.sn为字符串变量

test = s1 + s2 + s3 + s4 + s5;

4.

test = s1;
test += s2;
test += s3;
test += s4;
test += s5;

5.csn为字符串常量

test = cs1 + cs2 + cs3 + cs4 + cs5;

6.

test = cs1;
test += cs2;
test += cs3;
test += cs4;
test += cs5;

以上6种方式各循环10000000次,你能猜出他们执行所需时间的的顺序吗? 如果你是c++程序员,我觉得对于这个问题你可能会不占优势,你可能想到临时变量之类的吧.看测试代码:

            const int Num = 10000000;int end;string test = "";int start = Environment.TickCount;for (int i = 0; i < Num; i++){test = "I1" + "I2" + "I3" + "I4" + "I5";}end = Environment.TickCount;Console.WriteLine("字符串字面值:" + (end - start));start = Environment.TickCount;for (int i = 0; i < Num; i++){test = "I6";test += "I7";test += "I8";test += "I9";test += "I10";}end = Environment.TickCount;Console.WriteLine("字符串字面值:" + (end - start));string s1 = "e1";string s2 = "e2";string s3 = "e3";string s4 = "e4";string s5 = "e5";start = Environment.TickCount;for (int i = 0; i < Num; i++){test = s1 + s2 + s3 + s4 + s5;}end = Environment.TickCount;Console.WriteLine("变量:" + (end - start));s1 = "h1";s2 = "h2";s3 = "h3";s4 = "h4";s5 = "h5";start = Environment.TickCount;for (int i = 0; i < Num; i++){test = s1;test += s2;test += s3;test += s4;test += s5;}end = Environment.TickCount;Console.WriteLine("变量:" + (end - start));const string cs1 = "H1";const string cs2 = "H2";const string cs3 = "H3";const string cs4 = "H4";const string cs5 = "H5";start = Environment.TickCount;for (int i = 0; i < Num; i++){test = cs1 + cs2 + cs3 + cs4 + cs5;}end = Environment.TickCount;Console.WriteLine("字符串常量 :" + (end - start));start = Environment.TickCount;for (int i = 0; i < Num; i++){test = cs1;test += cs2;test += cs3;test += cs4;test += cs5;}end = Environment.TickCount;Console.WriteLine("字符串常量:" + (end - start));

你答对了吗?上答案啦!