Compilare: main.cpp: In function 'int main()': main.cpp:40:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("stup.in", "r", stdin); ^ main.cpp:41:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("stup.out", "w", stdout); ^ main.cpp:44:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &x, &y); ^ main.cpp:70:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^