diff options
Diffstat (limited to 'ch2/2-07.c')
-rw-r--r-- | ch2/2-07.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/ch2/2-07.c b/ch2/2-07.c new file mode 100644 index 0000000..bf9fed1 --- /dev/null +++ b/ch2/2-07.c @@ -0,0 +1,19 @@ +#include<stdio.h> + +/* + * Returns x with the n bits that begin at position p inverted (i.e., 1 changed + * into 0 and vice versa), leaving the others unchanged. + */ + +unsigned invert(unsigned x, unsigned p, unsigned n) { + // Create mask where bits should be flipped. + unsigned mask = ~(~0 << n) << (p + 1 - n); + + // Flip bits with mask. + return x ^ mask; +} + +int main() { + printf("%x\n", invert(0xaa, 3, 3)); + printf("%x\n", invert(0xff, 3, 3)); +} |