ublicRecta
gledoublel0doublet0doubler0doubleb0Recta
gle析构函数，在此函数体为空voidAssig
doubleldoubletdoublerdoublebdoublegetLeftretur
left以下四个函数皆为内联成员函数doublegetRightretur
rightdoublegetTopretur
topdoublegetBottomretur
bottomvoidShowdoubleAreadoublePerimeter构造函数，带缺省参数，缺省值为全0，在声明中指定Recta
gleRecta
gledoubleldoubletdoublerdoublebleftltoptrightrbottomb
fvoidRecta
gleAssig
doubleldoubletdoublerdoubleb赋值leftltoptrightrbottomb
voidRecta
gleShow成员函数直接使用私有的数据成员
cout