Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:12: warning: comparison between signed and unsigned integer expressions user.cpp: At global scope: user.cpp:19: warning: ISO C++ forbids declaration of ‘main’ with no type user.cpp: In function ‘int main()’: user.cpp:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result