Compilare: user.cpp: In function 'void df1(int)': user.cpp:21: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void df2(int, int)': user.cpp:34: 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:79: warning: comparison between signed and unsigned integer expressions user.cpp:99: warning: comparison between signed and unsigned integer expressions