Problem $9$ for Demonstration $1\mathrm{.}1$

$(15$ pts$)$ Write a C program which opens file$1$ which only contains this line:

dcab

and then opens the empty file$2.$ Your program should write acbd to file$2.$ You may only declare one uninitialized char variable and may not have any loops, con$-$ ditionals, or include statements, or library functions, and may not use lseek or do any arithmetic with ascii codes. No string constants $($such as abcd or acbd should appear in the file$).$ Solve the problem by only using system calls directly.

Enter your code $($apart from headers$)$ here:

int main$($void$)\{$