Programming

need some help please (if not against the rulez)
I am a bit stuck here because when entering data into the field, 0 is in memory 0x30...
I have read about alphanumeric shellcodes but doesn’t help much...
what I have done now :
written in asm a code that launches a root shell..., and tested it in C with the corresponding opcodes...
also I know how to rewrite the ebp register when launching the ch14 program...
and noticed too that eip points to the beginning of the shellcode array....
thx for your help