Compilare: user.cpp: In function ‘void structura()’: user.cpp:43:7: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] *p=NULL; ^ user.cpp: In function ‘void fisier()’: user.cpp:71:27: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] for (i=poz; s[i]>='a' && s[i]<='z' || s[i]<='9' && s[i]>='0'; i++) ^ user.cpp:73:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] nf[i-poz]=NULL; ^