Compilare: main.cpp: In function 'Matrix Inmultire(Matrix, Matrix)': main.cpp:30:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) ~~^~~~~~~~~~ main.cpp:31:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < a.size(); j++) ~~^~~~~~~~~~ main.cpp:32:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < a.size(); k++) ~~^~~~~~~~~~