pioni.cpp: In function 'int main()': pioni.cpp:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pioni.cpp:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pioni.cpp:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pioni.cpp:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pioni.cpp:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pioni.cpp:48: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result