输出结果是13,6……26楼已经正确解答
46楼的代码反汇编……
Microsoft Visual C++ 10.0.30319.1_RTM

a = 3;
00F7354E C7 45 F8 03 00 00 00 mov         dword ptr [a],3  
b = a++;
00F73555 8B 45 F8             mov         eax,dword ptr [a]  
00F73558 89 45 EC             mov         dword ptr [b],eax  
00F7355B 8B 4D F8             mov         ecx,dword ptr [a]  
00F7355E 83 C1 01             add         ecx,1  
00F73561 89 4D F8             mov         dword ptr [a],ecx  
b = ++a + b;
00F73564 8B 45 F8             mov         eax,dword ptr [a]  
00F73567 83 C0 01             add         eax,1  
00F7356A 89 45 F8             mov         dword ptr [a],eax  
00F7356D 8B 4D F8             mov         ecx,dword ptr [a]  
00F73570 03 4D EC             add         ecx,dword ptr [b]  
00F73573 89 4D EC             mov         dword ptr [b],ecx  
b =  (a++)  + b;
00F73576 8B 45 F8             mov         eax,dword ptr [a]  
00F73579 03 45 EC             add         eax,dword ptr [b]  
00F7357C 89 45 EC             mov         dword ptr [b],eax  
00F7357F 8B 4D F8             mov         ecx,dword ptr [a]  
00F73582 83 C1 01             add         ecx,1  
00F73585 89 4D F8             mov         dword ptr [a],ecx