Java：使用抽象类定义一个“形状类”，能够计算周长和面积。

[{"title":"（ 9 个子文件 6KB ） Java：使用抽象类定义一个“形状类”，能够计算周长和面积。","children":[{"title":"grith_area","children":[{"title":".project <span style='color:#111;'> 386B </span>","children":null,"spread":false},{"title":"bin","children":[{"title":"grith_area","children":[{"title":"Girth_Area.class <span style='color:#111;'> 810B </span>","children":null,"spread":false},{"title":"Circle.class <span style='color:#111;'> 946B </span>","children":null,"spread":false},{"title":"Rectangle.class <span style='color:#111;'> 954B </span>","children":null,"spread":false},{"title":"Shape.class <span style='color:#111;'> 298B </span>","children":null,"spread":false},{"title":"Triangle.class <span style='color:#111;'> 1.09KB </span>","children":null,"spread":false}],"spread":true}],"spread":true},{"title":".settings","children":[{"title":"org.eclipse.jdt.core.prefs <span style='color:#111;'> 598B </span>","children":null,"spread":false}],"spread":true},{"title":"src","children":[{"title":"grith_area","children":[{"title":"Girth_Area.java <span style='color:#111;'> 1.72KB </span>","children":null,"spread":false}],"spread":true}],"spread":true},{"title":".classpath <span style='color:#111;'> 301B </span>","children":null,"spread":false}],"spread":true}],"spread":true}]