replace.cpp: In function `int main()': replace.cpp:29: warning: assignment to non-pointer type `char' from NULL replace.cpp:29: warning: argument to non-pointer type `char' from NULL replace.cpp:32: warning: assignment to non-pointer type `char' from NULL replace.cpp:32: warning: argument to non-pointer type `char' from NULL replace.cpp:36: warning: assignment to non-pointer type `char' from NULL replace.cpp:36: warning: argument to non-pointer type `char' from NULL replace.cpp:43: warning: assignment to non-pointer type `char' from NULL replace.cpp:43: warning: argument to non-pointer type `char' from NULL