dir.cpp: In function `int main()': dir.cpp:16: warning: comparison between signed and unsigned integer expressions dir.cpp:24: warning: assignment to non-pointer type `char' from NULL dir.cpp:24: warning: argument to non-pointer type `char' from NULL dir.cpp:26: warning: NULL used in arithmetic dir.cpp:27: warning: assignment to non-pointer type `char' from NULL dir.cpp:27: warning: argument to non-pointer type `char' from NULL dir.cpp:29: warning: assignment to non-pointer type `char' from NULL dir.cpp:29: warning: argument to non-pointer type `char' from NULL