Compilare: user.cpp: In function ‘int main()’: user.cpp:22:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<strlen(s); i++) ^ user.cpp:29:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<strlen(s); j++) ^ user.cpp:45:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<strlen(s); i++) ^ user.cpp:47:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=i+1; j<strlen(s)-1; j++) ^ user.cpp:56:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k=0; k<strlen(s); k++) ^