Compilare: main.cpp: In function 'int main()': main.cpp:48:62: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.in","r",stdin),freopen("sdo.out","w",stdout); ^ main.cpp:48:62: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp: In function 'char N()': main.cpp:12:31: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(r,1,R,stdin),o=0; ^