Compilare: main.cpp: In function 'void read()': main.cpp:15:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ main.cpp:18:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^ main.cpp: In function 'int main()': main.cpp:30:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("xcabluri.in", "r", stdin); ^ main.cpp:31:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("xcabluri.out", "w", stdout); ^