Compilare: user.cpp: In function 'void df(long int, long int, long int)': user.cpp:19: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void df2(long int)': user.cpp:29: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void df3(long int, long int)': user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:65: warning: comparison between signed and unsigned integer expressions user.cpp:72: warning: comparison between signed and unsigned integer expressions user.cpp:98: warning: comparison between signed and unsigned integer expressions