Berkeley CS 61B Data Structures(in Java) Lab2 讨论帖

Testing constructors and toString():
The fraction f0 is 0/1
The fraction f1 is 3/1
The fraction f2 is 3/5
The fraction f3 is 3/5, which should equal f2

Testing add:
The sum of 3/1 and 3/5 is 18/5
The sum of 0/1, 3/1 and 3/5 is 18/5

Testing changeNumerator and fracs:
Now f3 is 7/20, which should be 7/20
The total number of Fraction objects is 6

Testing gcd:
The gcd of 2 and 10 is: 2
The gcd of 15 and 5 is: 5
The gcd of 24 and 18 is: 6
The gcd of 10 and 10 is: 10
The gcd of 21 and 400 is: 1

Testing constructors and toString():
The fraction f0 is 0/1
The fraction f1 is 3/1
The fraction f2 is 3/5
The fraction f3 is 3/5, which should equal f2

Testing add:
The sum of 3/1 and 3/5 is 18/5
The sum of 0/1, 3/1 and 3/5 is 18/5

Testing changeNumerator and fracs:
Now f3 is 7/20, which should be 7/20
The total number of Fraction objects is 7

Testing gcd:
The gcd of 2 and 10 is: 2
The gcd of 15 and 5 is: 5
The gcd of 24 and 18 is: 6
The gcd of 10 and 10 is: 10
The gcd of 21 and 400 is: 1

换了一个浏览器依旧不能上传图片... 那就也说一下心得吧。
lab2作业真的好，和lecture环环相扣，难易程度依次递增。听lecture的时候感觉听懂了，一到练习就懵逼。一上来连类里怎么调用方法都没想到。自己太辣鸡了。后来把lecture3翻出来重新听一遍才发觉之前有太多小点被遗漏了，shewchuk教授是我新晋男神讲的真清楚，是我自己没理解好。
还有大家看的好仔细呀...我都没发现System.out.println("The total number of Fraction objects is " +f3. fracs());那里还有一个f3. 这么一看fracs()函数确实和f3没关系，它调用的时候也不会分配this.
关于在构造函数中用this（）调用其他构造函数，除了上面大家的总结，还有以下几点： 使用this（）必须在起始行；一个constructor内只能调用一个另一个constructor；不能在constructor之外的任何函数调用constructor。

VarlarMorghulis 发表于 2018-7-22 22:49
换了一个浏览器依旧不能上传图片... 那就也说一下心得吧。
lab2作业真的好，和lecture环环相扣，难易程度 ...

啊不能发图的话我也粘贴一下console的结果好了TT
Testing constructors and toString():
The fraction f0 is 0/1
The fraction f1 is 3/1
The fraction f2 is 3/5
The fraction f3 is 3/5, which should equal f2

Testing add:
The sum of 3/1 and 3/5 is 18/5
The sum of 0/1, 3/1 and 3/5 is 18/5

Testing changeNumerator and fracs:
Now f3 is 7/20, which should be 7/20
The total number of Fraction objects is 7

Testing gcd:
The gcd of 2 and 10 is: 2
The gcd of 15 and 5 is: 5
The gcd of 24 and 18 is: 6
The gcd of 10 and 10 is: 10
The gcd of 21 and 400 is: 1

一开始很疑惑为什么f3没有调用toString或gcd也会进行约分，后来觉得是在system.out.println里系统自动调用了已修改过的toString，不知道对不对。

Finally~~~

上传截图打卡

作业打卡

调用已有对象的constructor忘记改了，返工了一下