Compilare: main.cpp: In function 'int main()': main.cpp:134:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < c.size(); i ++) ~~^~~~~~~~~~ main.cpp:147:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= c.size(); i ++) ~~^~~~~~~~~~~ main.cpp:151:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < r.size(); i ++) ~~^~~~~~~~~~ main.cpp:164:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= r.size(); i ++) ~~^~~~~~~~~~~