trafic.cpp: In function 'void read()': trafic.cpp:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result trafic.cpp:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result trafic.cpp: In function 'void bf(int, int)': trafic.cpp:42: warning: comparison between signed and unsigned integer expressions trafic.cpp: In function 'void cons_graph(int)': trafic.cpp:70: warning: comparison between signed and unsigned integer expressions trafic.cpp: In function 'int BF()': trafic.cpp:89: warning: comparison between signed and unsigned integer expressions trafic.cpp: In function 'int main()': trafic.cpp:129: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result trafic.cpp:130: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result