mahjong.cpp: In function 'void readdata()': mahjong.cpp:112: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mahjong.cpp:116: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mahjong.cpp: In function 'int main()': mahjong.cpp:122: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result mahjong.cpp:123: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result