th bit to zero?

 

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  • How do you set, clear, and toggle a single bit? 26 answers

    • You just have to replace the logical OR with a logical AND operation. You would use the & operator for that: 

    pt = pt & ~(1 << i);

    You have to invert your mask because logical AND ing with a 1 will maintain the bit while 0 will clear it... so you'd need to specify a 0 in the location that you want to clear. Specifically, doing 1 << i will give you a mask that is 000...010..000 where the 1 is in the bit position that you want, and inverting this will give 111...101...111 . Logical AND ing with this will clear the bit that you want.

    你可以坚持这一点： 

    // Set bit at position `bitpos` in `pt` to `bitval`
unsigned char bitpos = 1;
unsigned char pt = 0b01100001;
bool bitval = 1;

// Clear the bit
pt &= ~(1u << bitpos);
// Set the bit
pt |= (bitval << bitpos);
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