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Byte shift problem in integer conversion

I am reading 3 bytes in a binary that I need to convert to an integer.

I am using this code to read bytes:

LastNum last1Hz = new LastNum();
last1Hz.Freq = 1;
Byte[] LastNumBytes1Hz = new Byte[3];
Array.Copy(lap_info, (8 + (32 * k)), LastNumBytes1Hz, 0, 3);
last1Hz.NumData = LastNumBytes1Hz[2] << 16 + LastNumBytes1Hz[1] << 8 + LastNumBytes1Hz[0];

last1Hz.NumData

is integer

.

This seems to be a good way to convert bytes

to integers

in posts I've seen.

Here is a capture of the values ​​read:

enter image description here

But the integer is last1Hz.NumData

always 0.

I'm missing something but can't figure out what.

+3


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2 answers


You need to use parentheses (because append has higher precedence than bit offset):

int a = 0x87;
int b = 0x00;
int c = 0x00;

int x = c << 16 + b << 8 + a; // result 0
int z = (c << 16) + (b << 8) + a; // result 135


Your code should look like this:

last1Hz.NumData = (LastNumBytes1Hz[2] << 16) + (LastNumBytes1Hz[1] << 8) + LastNumBytes1Hz[0];
+4


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I think the problem is the order of priority. + evaluates to <Insert parentheses to evaluate bit shift first.



 last1Hz.NumData = (LastNumBytes1Hz[2] << 16) + (LastNumBytes1Hz[1] << 8) + LastNumBytes1Hz[0];
0


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