猜猜几种c#字符串连接所消耗时间的先后?-白红宇

猜猜几种c#字符串连接所消耗时间的先后?

阅读量：6611 次

发布时间：2019-06-24

本文共 2772 字，大约阅读时间需要 9 分钟。

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;

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

5.csn为字符串常量

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

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!