/in/exam3_matrix.cpp:13:1: error: prototype for 'intMatrix::intMatrix()' does not match any in class 'intMatrix'
 intMatrix::intMatrix() {
 ^~~~~~~~~
/in/exam3_matrix.cpp:8:1: error: candidates are: intMatrix::intMatrix(int, int, int)
 intMatrix::intMatrix(int x,int y, int mat) {
 ^~~~~~~~~
In file included from /in/exam3_matrix.cpp:6:0:
/in/compile/exam3_matrix.h:23:2: error:                 intMatrix::intMatrix(const intMatrix&)
  intMatrix(const intMatrix & that) {
  ^~~~~~~~~
/in/exam3_matrix.cpp: In member function 'void intMatrix::saveTo(std::__cxx11::string)':
/in/exam3_matrix.cpp:53:9: error: unused variable 'x' [-Werror=unused-variable]
     int x = this->rows;
         ^
/in/exam3_matrix.cpp:54:9: error: unused variable 'y' [-Werror=unused-variable]
     int y = this->cols;
         ^
cc1plus: all warnings being treated as errors