Compilare: main.cpp: In function 'int main()': main.cpp:16:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(a); i++) ~^~~~~~~~~~ main.cpp:32:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=strlen(a); i<strlen(b); i++) ~^~~~~~~~~~