Compilare: user.cpp: In function 'void df1(int)': user.cpp:20: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void df2(int, int)': user.cpp:33: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:64: warning: comparison between signed and unsigned integer expressions user.cpp:78: warning: comparison between signed and unsigned integer expressions user.cpp:94: warning: comparison between signed and unsigned integer expressions