Compilare: user.cpp: In function ‘int df2(int)’: user.cpp:14: warning: comparison between signed and unsigned integer expressions user.cpp:27: warning: no return statement in function returning non-void user.cpp: In function ‘int df(int, int, int)’: user.cpp:35: warning: comparison between signed and unsigned integer expressions user.cpp:42: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:69: warning: comparison between signed and unsigned integer expressions user.cpp:72: warning: comparison between signed and unsigned integer expressions user.cpp:75: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: comparison between signed and unsigned integer expressions user.cpp:84: warning: comparison between signed and unsigned integer expressions user.cpp:87: warning: comparison between signed and unsigned integer expressions