atac.cpp: In function 'int main()': atac.cpp:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result atac.cpp:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result atac.cpp:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result atac.cpp:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result atac.cpp:78: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result atac.cpp:83: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result atac.cpp: In function 'int ccw(dd, dd, dd)': atac.cpp:25: warning: control reaches end of non-void function