C#中for(;;)和while(true)之间的区别？

Question

从语法上来说,我看到它们无限循环,直到达到break语句,但它们是否编译为同一个东西？因为它没有条件可以检查吗？除了代码可读性之外,还有差别吗？

Answer 1

鉴于此输入:

private static void ForLoop()
{
    int n = 0;
    for (; ; )
    {
        Console.WriteLine(n++);
    }
}

private static void WhileLoop()
{
    int n = 0;
    while (true)
    {
        Console.WriteLine(n++);
    }
}

...你得到这个输出:

.method private hidebysig static void  ForLoop() cil managed
{
  // Code size       14 (0xe)
  .maxstack  3
  .locals init ([0] int32 n)
  IL_0000:  ldc.i4.0
  IL_0001:  stloc.0
  IL_0002:  ldloc.0
  IL_0003:  dup
  IL_0004:  ldc.i4.1
  IL_0005:  add
  IL_0006:  stloc.0
  IL_0007:  call       void [mscorlib]System.Console::WriteLine(int32)
  IL_000c:  br.s       IL_0002
} // end of method Program::ForLoop


.method private hidebysig static void  WhileLoop() cil managed
{
  // Code size       14 (0xe)
  .maxstack  3
  .locals init ([0] int32 n)
  IL_0000:  ldc.i4.0
  IL_0001:  stloc.0
  IL_0002:  ldloc.0
  IL_0003:  dup
  IL_0004:  ldc.i4.1
  IL_0005:  add
  IL_0006:  stloc.0
  IL_0007:  call       void [mscorlib]System.Console::WriteLine(int32)
  IL_000c:  br.s       IL_0002
} // end of method Program::WhileLoop

非常相似,我会说(相同,甚至).

Answer 2

在现代编译器中,绝对没有.

然而,从历史上看,for(;;)它实现为单跳,同时while(true)也检查为真.

我更喜欢while(true),因为它让我更清楚我在做什么.