[C Language] Note q = (++ j) + (++ j) Value

Different compilers may produce different codes, resulting in different results.

 

The Code is as follows:

 #include <stdio.h>    j =   q =(++j)+(++j)+(++ }

 

Environment: win7

Compiler: GCC

IDE: vc ++ 6.0/DEV-C ++

Result: q = 22

: Q = (++ j) + (++ mov eax, dword ptr [ebp-] Move J = add eax, add 1 to the Register eax value, eax = 0040103C mov dword ptr [ebp-], eax moves the register value to the variable j, j = 0040103F mov ecx, dword ptr [ebp-] Move J = add ecx, in the register, ecx +, j = mov dword ptr [ebp-], ecx moves the value on the register ecx to J, J = mov edx, dword ptr [ebp-] Move J = 7 to register edx = 0040104B add edx, dword ptr [ebp-] edx value + j at this time j =, edx = + 0040104E mov eax, dword ptr [ebp-] add j = add eax and eax to 1. In this case, register eax = mov dword ptr [ebp-], eax moves the eax value to j = add edx, dword ptr [ebp-] edx value = edx + j = + 0040105A mov dword ptr [ebp-0Ch], move the edx value to j =

 

Environment: win7

Compiler: GCC

IDE: VC ++ 2008

Running result: 24

  q =(++j)+(++j)+(++  003A1818  add         eax,   //eax = 6   003A1821  add         ecx,  ecx = 7   003A182A  add         edx,   edx = 8     003A1839  mov         dword ptr [q],eax