Compilare: user.cpp: In function ‘void arity(int)’: user.cpp:78:17: warning: NULL used in arithmetic [-Wpointer-arith] while(*p != NULL) ^ user.cpp: In function ‘void initial()’: user.cpp:98:27: warning: suggest parentheses around assignment used as truth value [-Wparentheses] b[0][i] = b[1][i] = v[0][i] = v[1][i] = 0; ^ user.cpp: In function ‘int main()’: user.cpp:112:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:117:31: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s[0]), gets(s[1]); ^ user.cpp:117:31: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] /tmp/ccoN4x13.o: In function `main': user.cpp:(.text.startup+0x98): warning: the `gets' function is dangerous and should not be used.