Super simplified 2-6 2-7, added 2-8

1 files changed, 19 insertions, 0 deletions

diff --git a/ch2/2-7.c b/ch2/2-7.c
new file mode 100644
index 0000000..bf9fed1
--- /dev/null
+++ b/ch2/2-7.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));
+}