《Cracking the Coding Inteview》——第5章：位操作——题目4

 1 // 5.4 Show what the code "n & (n - 1) == 0" means.
 2 #include <cstdio>
 3 using namespace std;
 4 
 5 int main()
 6 {
 7     unsigned int n;
 8     
 9     while (scanf("%u", &n) == 1) {
10         if ((n & n - 1) == 0) {
11             printf("%u is a power of 2.\n", n);
12         } else {
13             printf("%u is not a power of 2.\n", n);
14         }
15     }
16     
17     return 0;
18 }