Compilare: user.cpp: In function ‘void citire()’: user.cpp:97:9: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[k]=NULL; ^ user.cpp: In function ‘void afisare()’: user.cpp:109:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(a);i++) ^ user.cpp:108:15: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^