C#中非主流的换值方法

今天在csdn看见个人提问

 

1：

int a = 1, b = 2;

a = b + (b = a) * 0;

 mov         dword ptr [ebp-44h],1

 mov         dword ptr [ebp-48h],2 

 

 mov         eax,dword ptr [ebp-48h] 

 mov         dword ptr [ebp-58h],eax

 mov         eax,dword ptr [ebp-44h]

 mov         dword ptr [ebp-48h],eax 

 mov         eax,dword ptr [ebp-58h] 

 mov         dword ptr [ebp-44h],eax 

2：

int c = 2, d = 1;
int f = c;
c = d;
d = f;
 mov         dword ptr [ebp-4Ch],2 
2 mov         dword ptr [ebp-50h],1 
3 
4 mov         eax,dword ptr [ebp-4Ch] 
5 mov         dword ptr [ebp-54h],eax
6 mov         eax,dword ptr [ebp-50h]
7 mov         dword ptr [ebp-4Ch],eax
8 mov         eax,dword ptr [ebp-54h]
9 mov         dword ptr [ebp-50h],eax

 

很奇怪第一个例子的加号和乘号哪去了？ 这样就完成了换值

 

出这题的人真是个高手啊