Compilare: main.cpp: In function 'void solve()': main.cpp:19:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(a); i++) ~^~~~~~~~~~ main.cpp:25:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(a); i++) ~^~~~~~~~~~ main.cpp:34:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=strlen(a); i<strlen(b); i++) ~^~~~~~~~~~