八股考试 - 全面检测你的Java基础掌握情况
public class EvenSum {
public static void main(String[] args) {
int sum = 0;
for (int i = 2; i <= 100; i += 2) {
sum += i;
}
System.out.println("1到100之间所有偶数的和是:" + sum);
}
}
public class PrimeChecker {
public static boolean isPrime(int n) {
if (n <= 1) return false;
if (n <= 3) return true;
if (n % 2 == 0 || n % 3 == 0) return false;
for (int i = 5; i * i <= n; i += 6) {
if (n % i == 0 || n % (i + 2) == 0) {
return false;
}
}
return true;
}
public static void main(String[] args) {
System.out.println(isPrime(17)); // true
System.out.println(isPrime(18)); // false
}
}