采用面向对象的程序设计方法编写一个计算图形面积的类，程序应当能够计算并输出圆、矩形和三角形的面积。

[{"title":"（ 15 个子文件 25KB ） 采用面向对象的程序设计方法编写一个计算图形面积的类，程序应当能够计算并输出圆、矩形和三角形的面积。","children":[{"title":"S3-4","children":[{"title":"S3-4.suo <span style='color:#111;'> 16.50KB </span>","children":null,"spread":false},{"title":"S3-4","children":[{"title":"AreaCalculate.cs <span style='color:#111;'> 2.54KB </span>","children":null,"spread":false},{"title":"S3-4.csproj <span style='color:#111;'> 2.41KB </span>","children":null,"spread":false},{"title":"Shape.cs <span style='color:#111;'> 148B </span>","children":null,"spread":false},{"title":"Properties","children":[{"title":"AssemblyInfo.cs <span style='color:#111;'> 1.31KB </span>","children":null,"spread":false}],"spread":true},{"title":"obj","children":[{"title":"x86","children":[{"title":"Debug","children":[{"title":"TempPE","children":null,"spread":false},{"title":"S3-4.csproj.FileListAbsolute.txt <span style='color:#111;'> 465B </span>","children":null,"spread":false},{"title":"DesignTimeResolveAssemblyReferencesInput.cache <span style='color:#111;'> 5.71KB </span>","children":null,"spread":false},{"title":"S3-4.exe <span style='color:#111;'> 5.50KB </span>","children":null,"spread":false},{"title":"S3-4.csprojResolveAssemblyReference.cache <span style='color:#111;'> 6.79KB </span>","children":null,"spread":false},{"title":"S3-4.pdb <span style='color:#111;'> 15.50KB </span>","children":null,"spread":false}],"spread":true}],"spread":true}],"spread":true},{"title":"bin","children":[{"title":"Debug","children":[{"title":"S3-4.vshost.exe.manifest <span style='color:#111;'> 490B </span>","children":null,"spread":false},{"title":"S3-4.exe <span style='color:#111;'> 5.50KB </span>","children":null,"spread":false},{"title":"S3-4.pdb <span style='color:#111;'> 15.50KB </span>","children":null,"spread":false},{"title":"S3-4.vshost.exe <span style='color:#111;'> 11.33KB </span>","children":null,"spread":false}],"spread":true}],"spread":true}],"spread":true},{"title":"S3-4.sln <span style='color:#111;'> 854B </span>","children":null,"spread":false}],"spread":true}],"spread":true}]