Compilare: main.cpp: In member function 'bool ecuatie::solved_by(const std::vector<double>&)': main.cpp:18:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<double>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for(int i = 0; i < coef.size(); i++) sum += coef[i] * sol[i]; | ~~^~~~~~~~~~~~~ main.cpp: In function 'ecuatie operator*(double, const ecuatie&)': main.cpp:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<double>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 27 | for(int i = 0; i < ret.coef.size(); i++) { | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'ecuatie operator+(const ecuatie&, const ecuatie&)': main.cpp:40:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<double>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | for(int i = 0; i < ret.coef.size(); i++) { | ~~^~~~~~~~~~~~~~~~~