Standard input is empty
prog.cpp: In function ‘int main()’: prog.cpp:66: warning: suggest explicit braces to avoid ambiguous ‘else’ prog.cpp:49: warning: unused variable ‘op’ prog.cpp:47: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result prog.cpp:48: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result
Standard output is empty