arbnr.cpp: In function 'void read_tree(int)': arbnr.cpp:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result arbnr.cpp:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result arbnr.cpp: In function 'void represent_tree(nod*, char*&)': arbnr.cpp:29: warning: comparison between signed and unsigned integer expressions arbnr.cpp: In function 'void read_data()': arbnr.cpp:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result arbnr.cpp: In function 'int main()': arbnr.cpp:110: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result arbnr.cpp:111: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result