端口扫描的原理和种类

import java.util.Scanner;

public class Test6 {

//欧几里德 辗转相除法
public static int gcd(int a,int b) {
int r ;
while(b != 0) {
r = a % b ;
a = b;
b = r;
}
return a;
}
//最小公倍数的另一种解法
public static int gcdtwo(int a,int b){
while (a != b) {
if (a > b ) {
a = a -b;
} else {
b = b - a;
}
}
return a;
}
//最大公约数
public static int lcm(int a,int b) {
return a * b /gcd(a,b);
}
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("请输入第一个数:");
int a = input.nextInt();
System.out.println("请输入第二个数:");
int b = input.nextInt();
/*if (a < b) {
a = a+b;
b = a - b;
a = a - b;
}*/

System.out.println(gcdtwo(a,b));
System.out.println(lcm(a,b));

}
}