metrou.cpp: In function 'int dynamic(int)': metrou.cpp:87: warning: comparison between signed and unsigned integer expressions metrou.cpp: In function 'void spreadOccupy(int)': metrou.cpp:108: warning: comparison between signed and unsigned integer expressions metrou.cpp: In function 'void unspreadOccupy(int)': metrou.cpp:114: warning: comparison between signed and unsigned integer expressions metrou.cpp: In function 'int main()': metrou.cpp:120: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result metrou.cpp:121: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result