指针使用详解

jamasliu

#define                 MATCH_ROM               0x55                    //匹配ROM
const unsigned char code ROMData1[8] = {0x28, 0x33, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0xD7};        //U1
const unsigned char code ROMData2[8] = {0x28, 0x30, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0x8E};        //U2
const unsigned char code ROMData3[8] = {0x28, 0x31, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0xB9};        //U3
const unsigned char code ROMData4[8] = {0x28, 0x32, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0xE0};        //U4
const unsigned char code ROMData5[8] = {0x28, 0x34, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0x52};        //U5
const unsigned char code ROMData6[8] = {0x28, 0x35, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0x65};        //U6
const unsigned char code ROMData7[8] = {0x28, 0x36, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0x3C};        //U7
const unsigned char code ROMData8[8] = {0x28, 0x37, 0xC5, 0xB8, 0x00, 0x00, 0x00, 0x0B};        //U8

void MatchROM(const unsigned char *pMatchData)
{
        unsigned char i;

        Initialization();
        WriteByte(MATCH_ROM);
        for (i = 0; i < 8; i++)
        WriteByte(*(pMatchData + i));       
}


        switch (i)
        {
                case 1 : MatchROM(ROMData1); break;                        //匹配1
                case 2 : MatchROM(ROMData2); break;                        //匹配2
                case 3 : MatchROM(ROMData3); break;                        //匹配3
                case 4 : MatchROM(ROMData4); break;                        //匹配4       
                case 5 : MatchROM(ROMData5); break;                        //匹配5
                case 6 : MatchROM(ROMData6); break;                        //匹配6
                case 7 : MatchROM(ROMData7); break;                        //匹配7
                case 8 : MatchROM(ROMData8); break;                        //匹配8
        }


请大家详解下"WriteByte(*(pMatchData + i));"和"const unsigned char *pMatchData",这个值是怎么读出来的，谢谢！！！

jamasliu

大家帮忙顶下，请大家详解下WriteByte(*(pMatchData + i)); 是怎么赋值的，pMatchData+i,是怎么理解，谢谢！！！！

qlb1234

const unsigned char *pMatchData
-----------------------------------------------------
1.pMatchData
A variable named pMatchData.

2.*pMatchData
A variable named pMatchData that is a pointer.

3.const unsigned char *pMatchData
A variable named pMatchData that is a pointer points to constant unsigned character.

WriteByte(*(pMatchData + i))
--------------------------------------------
1.pMatchData
A variable named pMatchData that is a pointer points to constant unsigned character(as you recall).

2.(pMatchData + i)
An instance equals to pMatchData + i. The value is an address.

3.*(pMatchData + i)
Dereferencing the instance pMatchData + i, and you got the value stored in that address.
And note that implicit type conversion may take place if the type of the argument of WriteByte() is different with unsigned char.

wxty

还以为楼主在传教。。。

guzhongqi

标题取得很吸引眼球，坑爹啊。
指针就是个地址，加上*就变成对应地址的数据，加上类型就表示指针地址对应的数据是按类型存储的。

xingyuezh

楼上说的很对，其实你问的问题就按照指针的定义一步一步的计算就会得到

lusson

定义个2维的数组多好，switch都省了

jamasliu

明白点了，请问大哥怎么优化成二维数组，谢谢。。

Excellence

指针地址加1，然后*，就是取数据。