Compilare: user.cpp: In function ‘int main()’: user.cpp:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<strlen(s2); i++) ~^~~~~~~~~~~ user.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1; j<strlen(s1); j++) ~^~~~~~~~~~~