Compilare: user.cpp:25:13: warning: multi-character character constant [-Wmultichar] c[g][h]='NULL'; ^ user.cpp: In function ‘int main()’: user.cpp:25:12: warning: overflow in implicit constant conversion [-Woverflow] c[g][h]='NULL'; ^ user.cpp:14:9: warning: unused variable ‘f’ [-Wunused-variable] int d,e,f=0,g=0,h,j,k=0,l,m; ^ user.cpp:14:25: warning: unused variable ‘l’ [-Wunused-variable] int d,e,f=0,g=0,h,j,k=0,l,m; ^ user.cpp:14:27: warning: unused variable ‘m’ [-Wunused-variable] int d,e,f=0,g=0,h,j,k=0,l,m; ^ user.cpp:29:13: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] {j=j*10+(b[e]-'0'); ^