Compilare: main.cpp: In function 'int main()': main.cpp:60:9: warning: unused variable 'dr' [-Wunused-variable] int dr=0; ^~ main.cpp:29:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nc.in","r",stdin); ^ main.cpp:30:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nc.out","w",stdout); ^ main.cpp:37:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s",str); ^