Compilare: user.cpp: In function ‘int query(int, int)’: user.cpp:37:54: warning: operation on ‘dr’ may be undefined [-Wsequence-point] sum =sum*pw[arb[--dr].s]+arb[dr].f,sum%=p; ^ user.cpp: In function ‘int main()’: user.cpp:43:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rest.in","r",stdin); ^ user.cpp:44:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rest.out","w",stdout); ^ user.cpp:45:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d\n",&n,&b,&p); ^ user.cpp:47:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &arb[i+n].f); ^ user.cpp:50:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &m); ^ user.cpp:53:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &instr,&x,&y); ^