Compilare: main.cpp: In function 'int main()': main.cpp:46:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ main.cpp:47:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^ main.cpp:49:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ main.cpp:52:39: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets(buf, sizeof(buf), stdin); p = buf; ^ main.cpp:70:39: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets(buf, sizeof(buf), stdin); p = buf; ^