Compilare: user.cpp: In function ‘int main()’: user.cpp:18:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<strlen(aux);j++) ^ user.cpp:25:94: warning: NULL used in arithmetic [-Wpointer-arith] if(strlen(S[i])>strlen(S[j])||((strlen(S[i])==strlen(S[j]))&&(strcmp(S[i],S[j])==NULL))) ^ user.cpp:38:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(c<strlen(S[i])&&c2<strlen(S[j])) ^ user.cpp:38:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(c<strlen(S[i])&&c2<strlen(S[j])) ^ user.cpp:44:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(c==strlen(S[i])) ^ user.cpp:47:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(c=0;c<strlen(S[j]);c++) ^