Compilare: user.cpp: In function ‘bool sortare(elem, elem)’: user.cpp:13:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<strlen(a.s);j++) ^ user.cpp: In function ‘bool lafel(elem, elem)’: user.cpp:25:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<strlen(a.s);k++) ^ user.cpp: In function ‘void cantitate()’: user.cpp:54:16: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] v[i].s[aux]=NULL; ^ user.cpp: In function ‘int main()’: user.cpp:106:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p<strlen(s)) cantitate(); ^