tj.cpp: In function 'int main()': tj.cpp:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result tj.cpp:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result tj.cpp:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result tj.cpp:45: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result tj.cpp:50: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result