compress.cpp: In function `std::vector<char, std::allocator<char> > parse()': compress.cpp:28: warning: NULL used in arithmetic compress.cpp:34: warning: comparison between signed and unsigned integer expressions compress.cpp: In function `int main()': compress.cpp:57: warning: comparison between signed and unsigned integer expressions /tmp/ccGdDrfV.o(.text+0x338): In function `main': : the `gets' function is dangerous and should not be used.