20 class Matrix {  class
25     Matrix() {}  in Matrix()  function in Matrix
26     Matrix(float z) {  in Matrix()  function in Matrix
31     friend Matrix operator-(const Matrix& x) {  in operator -()
32         Matrix result;  in operator -()
38     friend Matrix operator+(const Matrix& x, const Matrix& y) {  in operator +()
39         Matrix result;  in operator +()
45     friend Matrix operator-(const Matrix& x, const Matrix& y) {  in operator -()
46         Matrix result;  in operator -()
52     friend Matrix operator*(const Matrix& x, const Matrix& y) {  in operator *()
53         Matrix result(0);  in operator *()