Compilare: user.cpp: In function ‘void p1()’: user.cpp:16:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(s); i++) ^ user.cpp: In function ‘void p2()’: user.cpp:26:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i<strlen(s); i++) ^ user.cpp:29:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i+1; j<strlen(s); j++) ^