一个对角矩阵，有如下共享成员，输入、输出、加减乘、转置等函数。结果都是一个用一位数组表示的对角矩阵。重载运算符<<,>>,+,-和*。-A diagonal matrix, there are shared members, input, output, subtraction multiplication, transpose and other functions. The result is an array represented by a diagonal matrix. Overloaded operator < < , > > ,+,- and*.