#include <stdio.h>
int highest_power_of_2_less_or_equal_to_n(int n) {
int power = 0;
for (int i = n; i >= 1; i--) {
// i == power of 2 ?
if ((i & (i - 1)) == 0) { // 10 (1010) 9 (1001) 8 (1000) 7 (0111)
power = i;
break;
}
}
return power;
}
int main()
{
int n = 17;
printf("%i\n", highest_power_of_2_less_or_equal_to_n(n));
n = 10;
printf("%i\n", highest_power_of_2_less_or_equal_to_n(n));
n = 64;
printf("%i\n", highest_power_of_2_less_or_equal_to_n(n));
return 0;
}
/*
run:
16
8
64
*/