#include  
#include  


# define UINT32 unsigned int 
# define UINT16 unsigned short int 
# define UCHAR8 unsigned char 

//define size end 
Typedef enum _NetWorkDataEndianEnum 
{
NET_BYTE_BIG_ENDIAN=0 x55,//big end 
NET_BYTE_LITTLE_ENDIAN=0 xaa//small end 
} NetByteOrder; 

UINT32 GetLongFromBuffer (UCHAR8 * & amp; BufferPtr, NetByteOrder NetByteOrder) 
{
It *//* define the value and init 
UINT32 value=https://bbs.csdn.net/topics/0U; 
/* */
If (bufferPtr!=NULL) 
{
The switch (netByteOrder) 
{
Case NET_BYTE_BIG_ENDIAN: 
{
Value=https://bbs.csdn.net/topics/(* (bufferPtr + 0) <24) + (* (bufferPtr + 1) <16) + (* (bufferPtr + 2) <8) + (* (bufferPtr + 3) <0); 
Printf ("====& gt; The value [0] : 02 x % \ n ", * (bufferPtr + 0)); 
Printf ("====& gt; The value [1] : 02 x % \ n ", * (bufferPtr + 1)); 
Printf ("====& gt; The value [2] : 02 x % \ n ", * (bufferPtr + 2)); 
Printf ("====& gt; The value [3] : 02 x % \ n ", * (bufferPtr + 3)); 

Printf ("===========& gt; 08 x value: 0 x % \ n ", value); 

//bufferPtr=bufferPtr + 4; 
} 
break; 
Case NET_BYTE_LITTLE_ENDIAN: 
{
Value=https://bbs.csdn.net/topics/(UINT32) (((UINT32) (* (bufferPtr + 3)) <24) + (UINT32) ((UINT32) (bufferPtr + 2) (*) <16) + ((UINT32) (* (bufferPtr + 1)) <8) + ((UINT32) (* (bufferPtr + 0)) <0)); 
//bufferPtr=bufferPtr + 4; 
} 
break; 
Default: 
break; 
} 
} 
The return value. 
} 

UINT16 GetBytesFromBuffer (UCHAR8 * ptrDst, UCHAR8 * & amp; PtrSrc, UINT16 bytesNum) 
{
If (NULL==ptrDst | | ptrSrc=NULL https://bbs.csdn.net/topics/=
{
return 0; 
} 

for(int i=0; i<4. I++) 
{
Printf ("====& gt; PtrSrc: 02 x % \ n ", * (ptrSrc + I)); 
} 

Memcpy (ptrDst ptrSrc, bytesNum); 

for(int i=0; i<4. I++) 
{
Printf ("====& gt; PtrDst: 02 x % \ n ", * (ptrDst + I)); 
} 

Return bytesNum; 
} 

Int main (int arg c, char * argv []) 
{
QCoreApplication ab (arg c, argv); 

UCHAR8 p [4]; 
for(int i=0; i<4. I++) 
{
P [I]=I;//p: 0 x00010203 
} 
UCHAR8 * pTemp=p; 

UINT32 _parameter1;//alarm parameters 1 
_parameter1=GetLongFromBuffer (pTemp NET_BYTE_BIG_ENDIAN); 

UINT32 _parameter2;//alarm parameters 2 
GetBytesFromBuffer ((UCHAR8 *) & amp; _parameter2, pTemp, 4); 

Printf ("===========& gt; 08 _para1:0 x % x \ n ", _parameter1); 
Printf ("===========& gt; 08 _para2:0 x % x \ n ", _parameter2); 

The return type ab. The exec (); 
} 

Results:


Don't quite understand, why the second result is different than the first one? Please welcome leaders teach, haha