Question

Stopwatch t1 = new Stopwatch();

t1.Start();
int i = 0;
for (int j = 0; j < 2000000001; j++)
     i += 1;
t1.Stop();



Stopwatch t2 = new Stopwatch();

t2.Start();
int k = 0;
for (int j = 0; j < 2000000001; j++)
{
     k += 1;
}
t2.Stop();

Console.WriteLine(t1.Elapsed);
Console.WriteLine(t2.Elapsed);

Console.ReadLine();

O / P：

00:00:05.0266990

00:00:04.7179756

性能还取决于变量名吗？

Answer 1

不，省略花括号对性能没有任何影响。你看到的差异可能是由于程序在一开始就变暖了。交换这两个代码块，你会看到相同的差异或没有。

如果您在发布模式下构建程序并在ILSpy （ILSpy版本2.1.0.1603）中打开可执行文件，那么您将看到已添加花括号。：

private static void Main(string[] args)
{
    Stopwatch t = new Stopwatch();
    t.Start();
    int i = 0;
    for (int j = 0; j < 2000000001; j++)
    {
        i++;
    }
    t.Stop();
    Stopwatch t2 = new Stopwatch();
    t2.Start();
    int k = 0;
    for (int l = 0; l < 2000000001; l++)
    {
        k++;
    }
    t2.Stop();
    Console.WriteLine(t.Elapsed);
    Console.WriteLine(t2.Elapsed);
    Console.ReadLine();
}

原始代码：

Stopwatch t1 = new Stopwatch();
t1.Start();
int i = 0;
for (int j = 0; j < 2000000001; j++)
    i += 1;
t1.Stop();
Stopwatch t2 = new Stopwatch();

t2.Start();
int k = 0;
for (int j = 0; j < 2000000001; j++)
{
    k += 1;
}
t2.Stop();

省略for-statement / if-statement的花括号会导致性能问题？

1 个答案: