Eroare de compilare: user.cpp:1:22: error: iostream.h: No such file or directory user.cpp:2:21: error: fstream.h: No such file or directory user.cpp:4: error: ‘ifstream’ does not name a type user.cpp:5: error: ‘ofstream’ does not name a type user.cpp: In function ‘int main()’: user.cpp:21: error: ‘f’ was not declared in this scope user.cpp:26: error: ‘NULL’ was not declared in this scope user.cpp:35: error: ‘NULL’ was not declared in this scope user.cpp:47: error: ‘g’ was not declared in this scope user.cpp: In function ‘void link(tnod*, tnod*)’: user.cpp:56: error: ‘NULL’ was not declared in this scope user.cpp:57: error: ‘NULL’ was not declared in this scope user.cpp:58: error: ‘NULL’ was not declared in this scope user.cpp:59: error: ‘NULL’ was not declared in this scope user.cpp: In function ‘int dfs(tnod*)’: user.cpp:67: error: ‘NULL’ was not declared in this scope user.cpp:70: error: ‘NULL’ was not declared in this scope user.cpp:71: error: ‘NULL’ was not declared in this scope