Compilare: main.cpp: In function 'int main()': main.cpp:81:103: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.in","r",stdin),freopen("heavypath.out","w",stdout),fread(ra,1,M,stdin),n=A(),m=A(); ^ main.cpp:81:103: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:81:103: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp: In function 'char N()': main.cpp:12:33: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ra,1,P,stdin),ro=0; ^