Write a function in C called that takes a string and return a new string built from this string after replacing each alphabetical character by the opposite alphabetical character.

$\text{'}$a$\text{'}$becomes $\text{'}$z$\text{'},\text{'}$Z$\text{'}$becomes $\text{'}$A$\text{'}\text{'}$d$\text{'}$becomes $\text{'}$w$\text{'},\text{'}$M$\text{'}$becomes $\text{'}$N$\text{'}$ and so on$.$

Case is not changed.

Must not use sprintf or other libc functions.

Input: "abc" Output: $"$zyx$"$

char$*$ a$\_$mirror$($char$*$ str$)$

$\{$

for $($i $=0$; i $<$ strlen$($str$)$; i$++)$

$\{$

if $($str$[$i$]>=97$ && str$[$i$]<=122)$

str$[$i$]=(\text{'}$m$\text{'}-($str$[$i$]-\text{'}$n$\text{'}))$;

else if $($str$[$i$]>=65$ && str$[$i$]<=90)$

str$[$i$]=(\text{'}$M$\text{'}-($str$[$i$]-\text{'}$N$\text{'}))$;

else

str$[$i$]=$ str$[$i$]$;

$\}$

return str;

$\}$