mxl.cpp: In function 'void read()': mxl.cpp:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result mxl.cpp:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp:45: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp:56: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result mxl.cpp: In function 'void write()': mxl.cpp:91: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result