建立一个二维坐标系的类TwoCoor，用X,Y表示坐标值，实现两个坐标点的加减运算，计算两个坐标点间的距离，并用重载输入/输出运算符，使之能够直接输入/输出坐标点的坐-The establishment of a two-dimensional coordinate system of the type TwoCoor, with X, Y coordinate values that realize the two coordinate points of addition and subtraction operations to calculate the distance between two coordinate points, and use heavy input/output operator, to enable direct Input/Output coordinates of the sitting