Compilare: user.cpp: In function ‘void lee(int, int, int)’: user.cpp:30:39: warning: statement has no effect [-Wunused-value] if (nr==r) {b[x1][x2]==-1; ok=true; return;} p=r+1; r=nr; ^ user.cpp: In function ‘int main()’: user.cpp:38:28: warning: format ‘%c’ expects a matching ‘char*’ argument [-Wformat=] scanf("%d%c",&n); ^