Compilare: user.cpp: In function ‘int main()’: user.cpp:59:16: warning: NULL used in arithmetic [-Wpointer-arith] if(p[i] == NULL){printf("-1"); return 0;} ^ user.cpp:60:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] p[n + 1] = NULL; ^ user.cpp:34:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("match.in", "r", stdin); ^ user.cpp:35:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("match.out", "w", stdout); ^ user.cpp:36:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s + 1); ^