类和方法而调用

package 四则运算;

public class a {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Yunsuan a=new Yunsuan();
		int i;
		for(i=0;i<100;i++)
		{
			a.aa();
		}		
		}

}

package 四则运算;

import java.util.Random;

public class Yunsuan {
	int a;
	int b;
	int c;
	char s;
	public void aa()
	{
		Random random = new Random();
		a=random.nextInt(100);
		b=random.nextInt(100);
		c=random.nextInt(4);
		if(c==0)
		{
			s=‘+‘;
		}
		else if(c==1)
		{
			s=‘-‘;
		}
		else if(c==2)
		{
			s=‘*‘;
		}
		else
		{
			s=‘/‘;
		}
		System.out.print(a);
        System.out.print(s);
        System.out.print(b);
        System.out.print("=");
        System.out.print("  ");
	}
	
}

package 四则运算;

import java.util.Random;

public class aa {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		a();
	}
	private static void a() {
		// TODO Auto-generated method stub
		 int a,b;
		 int i;
         for(i=0;i<10;i++)
         {
         Random random = new Random();
         a=random.nextInt(100);
         b=random.nextInt(100);
         zz(a,b);         
         }
	}
	private static void zz(int a, int b) {
		// TODO Auto-generated method stub
		 char s;
		 int c;
		 Random random = new Random();
		 c=random.nextInt(4);
         if(c==0)
         {
        	 s=‘+‘;
         }
         else if(c==1)
         {
        	 s=‘-‘;
         }
         else if(c==2)
         {
        	 s=‘*‘;
         }
         else
         {
        	 s=‘/‘;
         }
         System.out.print(a);
         System.out.print(s);
         System.out.print(b);
         System.out.print("=");
         System.out.print("   ");
		
	}

}