5.2

import java.util.Random;


public class test {
    private int a;
    private int b;
    int c;
    public int  jia(int a,int b)
    {
    
        System.out.println(""+a);
        System.out.println(""+b);
        c = a+b;
        System.out.println("a+"+"b"+"="+(a+b+"\n"));
        return c;
        
    }
    public int  jian(int a,int b)
    {
        
        System.out.println(""+a);
        System.out.println(""+b);
        c=a-b;
        System.out.println("a-"+"b"+"="+(a-b)+"\n");
        return c;
        
        
    }
    public int Cheng(int a,int b)
    {   
        System.out.println(""+a);
        System.out.println(""+b);
        c=a*b;
        System.out.println("a*"+"b"+"="+(a*b)+"\n");
        return c;
    }
    public double  Chu(int a,int b)
    {
        double c;
        c=(double) (Math.round((a/b)*100/100.0));
        System.out.println(""+a);
        System.out.println(""+b);
        if(b!=0)
            System.out.println("c=a/b="+(c)+"\n");
        else
            throw new ArithmeticException();
            System.out.println("分母不能为0！");
              
            return c;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         test Jia=new test();
         Jia.jia(5, 3);
         test Jian=new test();
         Jian.jian(6,2);
         test cheng=new test();
         cheng.Cheng(6,5);
         test chu=new test();
         chu.Chu(3,0);
         
    }

}

import java.util.Random;


public class FZ {
    private int a;
    private int b;
    int c;
    public int  jia(int a,int b)
    {
    
        System.out.println(""+a);
        System.out.println(""+b);
        c = a+b;
        System.out.println("a+"+"b"+"="+(a+b+"\n"));
        return c;
        
    }
    public int  jian(int a,int b)
    {
        
        System.out.println(""+a);
        System.out.println(""+b);
        c=a-b;
        System.out.println("a-"+"b"+"="+(a-b)+"\n");
        return c;
        
        
    }
    public int Cheng(int a,int b)
    {   
        System.out.println(""+a);
        System.out.println(""+b);
        c=a*b;
        System.out.println("a*"+"b"+"="+(a*b)+"\n");
        return c;
    }
    public double  Chu(int a,int b)
    {
        double c;
        c=(double) (Math.round((a/b)*100/100.0));
        System.out.println(""+a);
        System.out.println(""+b);
        if(b!=0)
            System.out.println("c=a/b="+(c)+"\n");
        else
            throw new ArithmeticException();
            System.out.println("分母不能为0！");
              
            return c;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         FZ Jia=new FZ();
         Jia.jia(5, 3);
         FZ Jian=new FZ();
         Jian.jian(6,2);
         FZ cheng=new FZ();
         cheng.Cheng(6,5);
         FZ chu=new FZ();
         chu.Chu(3,0);
         
    }

}

总结：了解了测试后发现测试是一个很好的功能，它能及时发现错误，提高开发效率。

        如果对测试还不是很懂的同学可以在慕课网学习，那里有详细方法。