Compilare: main.cpp: In function 'std::vector<std::vector<long double> > prod(std::vector<std::vector<long double> >, std::vector<std::vector<long double> >)': main.cpp:14:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<long double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 14 | for(int i=0;i<mat1.size();i++){ | ~^~~~~~~~~~~~ main.cpp:15:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | for(int j=0;j<mat2[0].size();j++){ | ~^~~~~~~~~~~~~~~ main.cpp:17:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<long double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 17 | for(int y=0;y<mat2.size();y++){ | ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:50:11: warning: unused variable 'j' [-Wunused-variable] 50 | int i,j,n,m; | ^