Compilare: user.cpp: In function ‘int query(int, int, int, int)’: user.cpp:48:88: warning: operation on ‘xld’ may be undefined [-Wsequence-point] return query(xru, yru) + query(--xld, --yld) - query(xru, yld) - query(xld, yru); ^ user.cpp:48:88: warning: operation on ‘yld’ may be undefined [-Wsequence-point] user.cpp: In function ‘int main()’: user.cpp:67:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<s[i].size(); ++j) { ^ user.cpp:71:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<s[i].size(); ++j) { ^ user.cpp:54:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evantai.in", "r", stdin); ^ user.cpp:55:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evantai.out", "w", stdout); ^ user.cpp:58:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:60:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^