Compilare: main.cpp: In function 'int main()': main.cpp:20:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(s); i++) ~^~~~~~~~~~ main.cpp:28:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<strlen(s); i++) ~^~~~~~~~~~ main.cpp:32:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i+1; j<strlen(s); j++) ~^~~~~~~~~~