Compilare: main.cpp: In function 'int main()': main.cpp:30:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 1 ; i <= s2.size() ; ++ i ) { ~~^~~~~~~~~~~~ main.cpp:34:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < s1.size() ; ++ i ) { ~~^~~~~~~~~~~ main.cpp:40:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < s1.size() ; ++ i ) { ~~^~~~~~~~~~~ main.cpp:51:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( ; i < s2.size() ; ++ i ) { ~~^~~~~~~~~~~ main.cpp:21:25: warning: unused variable 'j' [-Wunused-variable] int i , hash1 = 0 , j , hash2 = 0 ; ^