Compilare: main.cpp: In function 'void Poligon()': main.cpp:74:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < p1.size() - 1;++i) ~~^~~~~~~~~~~~~~~ main.cpp:79:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0;j < p2.size() && cross_product(p1[i],p1[i+1],p2[j]) < 0;++j); ~~^~~~~~~~~~~ main.cpp:81:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( j != p2.size()) ~~^~~~~~~~~~~~~ main.cpp:87:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0;j < p2.size() - 1;++j) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'int calculate_area()': main.cpp:126:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < p.size() - 1;++i) ~~^~~~~~~~~~~~~~ main.cpp:130:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^