Compilare: user.cpp: In function ‘bool cmp(interval, interval)’: user.cpp:17:43: warning: operation on ‘a2.interval::y’ may be undefined [-Wsequence-point] a1.y = a1.y + a2.y - (a2.y = a1.y); ^ user.cpp: In function ‘int main()’: user.cpp:34:18: warning: variable ‘l’ set but not used [-Wunused-but-set-variable] int sol = 1, l = a[1].x, r = a[1].y; ^ user.cpp:25:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reactivi.in", "r", stdin); ^ user.cpp:28:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:30:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a[i].x, &a[i].y); ^