hawaii.cpp: In function 'int main()': hawaii.cpp:24: warning: unused variable 'a' hawaii.cpp:24: warning: unused variable 'b' hawaii.cpp:24: warning: unused variable 'c' hawaii.cpp:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result hawaii.cpp:21: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result hawaii.cpp:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result hawaii.cpp:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result