Bitfiields in C how to?

[madhu542]

Hi,

I pasted my problem (below), need solution for the same

/* Counting bits from left to right (least significant bit is bit 0 and
* most significant is bit 31), the following describes the encoding pattern.
* All values can be assumed to be integers for simplicity
*
* bit 7 to bit 0 : (8 bits) represent the temperature
* bit 8, 9, 10 : UNUSED
* bit 17 to bit 11 : (7 bits) represent the humidity
* bit 18 : UNUSED
* bit 22 to bit 19 : (4 bits) represent the rainfall in inches
*/

I have a (below) function which will return int valve containing all the above senser values in it.

int getSensor() {
return 2543133;
}

Using bitfields how to process this and get correct values?

can anybody help me please!

[S_M_A]

See this http://en.wikipedia.org/wiki/Bit_field but do not skip reading of the drawback section

[greve]

You may use bitwise filtering plus bitshift to isolate the requested information, probably like:

struct TClimate
    {
    int m_Temperature;
    int m_Humidity;
    int m_LevelOfRain;
    };


TClimate ChopValue(const unsigned long ValueReadFromStation)
    {
    TClimate Result;

    Result.m_Temperature= ValueReadFromStation& 0x0000000F;
    Result.m_Humidity=        ValueReadFromStation& 0x0003F800;
    Result.m_Humidity>>= 11;
    Result.m_LevelOfRain=   ValueReadFromStation& 0x00780000;
    Result.m_LevelOfRain>>= 19;

    return Result;
    }

Hope this helps,
Thomas