Compilare: user.cpp: In member function ‘matrix matrix::operator+(matrix)’: user.cpp:65:29: warning: division by zero [-Wdiv-by-zero] int error = 0 / 0; ^ user.cpp:65:17: warning: unused variable ‘error’ [-Wunused-variable] int error = 0 / 0; ^ user.cpp: In member function ‘matrix matrix::operator*(matrix)’: user.cpp:79:29: warning: division by zero [-Wdiv-by-zero] int error = 0 / 0; ^ user.cpp:79:17: warning: unused variable ‘error’ [-Wunused-variable] int error = 0 / 0; ^ user.cpp: In function ‘int main()’: user.cpp:110:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(inputFile.c_str(), "r", stdin); ^ user.cpp:111:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(outputFile.c_str(), "w", stdout); ^ user.cpp:114:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &T, &MOD); ^ user.cpp:135:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &N); ^