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Read 'N' bit from a byte

I need to read a specific bit from a byte. The value i want to test is 0 or 1.

unsigned char Buffer[0]=2; 
//or binary 0b00000010

How can i read n bit from buffer. If it's 0 or 1? Example if 7 bit from byte is 0 or 1

Solution

  • You must define precisely how you count the bits:

    • starting at 0 or 1
    • from least significant to most significant or the other way?

    Assuming bit 0 is the least significant, you can get bit 7 with this expression:

    int bit7 = ((unsigned char)Buffer[0] >> 7) & 1;

    Here is a generic loop:

    for (int i = 7; i >= 0; i--) {
    putchar('0' + (((unsigned char)Buffer[0] >> i) & 1));
}