guess.cpp: In function 'int back(int)': guess.cpp:29: warning: comparison between signed and unsigned integer expressions guess.cpp:34: warning: comparison between signed and unsigned integer expressions guess.cpp:36: warning: comparison between signed and unsigned integer expressions guess.cpp:40: warning: comparison between signed and unsigned integer expressions guess.cpp: In function 'int main()': guess.cpp:50: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result guess.cpp:51: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result guess.cpp:55: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result guess.cpp:58: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result