unsigned long long int num = 0LL;
for (int i = 0; i < 64; i+= 2)
num |= 1LL << i;
printf("%llu\n", num);
Looks good however I have a few comments:
Instead of unsigned long long int I would use uint64_t.
You are using the format qualifier ll which is for signed long long.
Correct format specifier is llu
uint64_t result = 0llu;
for (int i = 0; i < 64; i += 2) {
result |= (1llu << i);
}
printf("Result is: %llu\n", result);