Compilare: main.cpp:8:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In function 'int main()': main.cpp:23:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp:30:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i + 1; j < v.size(); j++) ~~^~~~~~~~~~