计算长方形的周长和面积(类和对象)

import java.util.*;
class Rect{
	int a;
	int b;
	Rect(int a){
		if(a<0) {
			a=0;
		}
		else {
			this.a=a;
		}
		System.out.println(a+" "+a+" "+4*a+" "+a*a);
	}
	Rect(int a,int b){
		if(a<0||b<0) {
			a=0;
			b=0;
		}
		else {
			this.a=a;
			this.b=b;
		}
		System.out.println(a+" "+b+" "+2*(a+b)+" "+a*b);
	}
}
public class Main{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()) {
			String str=sc.nextLine();
			char a[]=str.toCharArray();
			int k=1;
			for(int i=0;i