algebra.cpp: In function 'bool Match(int)': algebra.cpp:31: warning: comparison between signed and unsigned integer expressions algebra.cpp:38: warning: comparison between signed and unsigned integer expressions algebra.cpp: In function 'int main()': algebra.cpp:93: warning: comparison between signed and unsigned integer expressions algebra.cpp:84: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result algebra.cpp:85: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result algebra.cpp:87: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result algebra.cpp:90: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result