Compilare: user.cpp: In function ‘bool comparator(punct, punct)’: user.cpp:58:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] else if(a.x == b.x) ^ user.cpp: In function ‘int main()’: user.cpp:122:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v.size(); i++) { ^