一个很简单的问题。关于代码的执行速度。

Question

public static void main()
{
    int a=5;
    Console.WriteLine("{0},{1},{2}",a,a,a);    //第二种
    int a=5;
    Object o=a;
    Console.WriteLine("{0},{1},{2}",o,o,o);
}
那种速度快？

Answer 1

肯定第一种撒至少可以省略Object o=a;
这一步

Answer 2

第一种的IL
.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // 代码大小       33 (0x21)
  .maxstack  4
  .locals init (int32 V_0)
  IL_0000:  nop
  IL_0001:  ldc.i4.5
  IL_0002:  stloc.0
  IL_0003:  ldstr      "{0},{1},{2}"
  IL_0008:  ldloc.0
  IL_0009:  box        [mscorlib]System.Int32
  IL_000e:  ldloc.0
  IL_000f:  box        [mscorlib]System.Int32
  IL_0014:  ldloc.0
  IL_0015:  box        [mscorlib]System.Int32
  IL_001a:  call       void [mscorlib]System.Console::WriteLine(string,
                                                                object,
                                                                object,
                                                                object)
  IL_001f:  nop
  IL_0020:  ret
} // end of method Program::Main
第二种的 IL.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // 代码大小       25 (0x19)
  .maxstack  4
  .locals init (int32 V_0,
           object V_1)
  IL_0000:  nop
  IL_0001:  ldc.i4.5
  IL_0002:  stloc.0
  IL_0003:  ldloc.0
  IL_0004:  box        [mscorlib]System.Int32
  IL_0009:  stloc.1
  IL_000a:  ldstr      "{0},{1},{2}"
  IL_000f:  ldloc.1
  IL_0010:  ldloc.1
  IL_0011:  ldloc.1
  IL_0012:  call       void [mscorlib]System.Console::WriteLine(string,
                                                                object,
                                                                object,
                                                                object)
  IL_0017:  nop
  IL_0018:  ret
} // end of method Program::Main

Answer 3

第一种 需要把三个 a 都装箱第二种 只需要把a装到o里面