Compilare: user.cpp: In function ‘int e_valid(int)’: user.cpp:7:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(k>1) if(!a[st[k-1]][st[k]]) return 0; ^ user.cpp:6:9: warning: unused variable ‘i’ [-Wunused-variable] { int i; ^ user.cpp: In function ‘void afisare(int)’: user.cpp:17:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘void backtr(int)’: user.cpp:39:9: warning: unused variable ‘i’ [-Wunused-variable] { int i,vef; ^ user.cpp: In function ‘int bcktr(int)’: user.cpp:71:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(e_valid2(k)) if(k==n) aflu(); ^ user.cpp:75:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^