Compilare: user.cpp: In function ‘void bell()’: user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs(int)’: user.cpp:56: warning: comparison between signed and unsigned integer expressions user.cpp:66: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:99: warning: comparison between signed and unsigned integer expressions user.cpp:85: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:88: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result