unsigned char ptrData[9]={0x02,0x11,0x04,0x03,0x25,0x07,0x01,0x00,0x43}
//方法1
unsigned int sCod=0;
sCod = *(ptrData+7);
sCod = sCod<<8 ;
sCod = sCod + *(ptrData+8);
//方法2
unsigned int sCod1=0;
sCod1 = *(ptrData+7);
sCod1 = sCod1<<8 + *(ptrData+8);
方法1算出来的sCod 值是正确的;
方法2算出来的sCod1 值是错误的;
该问题的原因已经找到:
方法2出现错误的原因是没有把符号的优先级搞清楚。+号的优先级是高于<<号的,所以应该修改为:
sCod1 = (sCod1<<8) + *(ptrData+8);