sant.cpp: In function 'int main()': sant.cpp:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sant.cpp:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sant.cpp:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sant.cpp:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result