Replace char to char in a string
<p>i need make one replace char to char in one string, i need that is make to original string.</p>

<p>the replace is A to T, T to A, C to G and G to C</p>

<p>ex: ACGTA with replace out is TGCAT</p>

<p>im search in google and cant find one solution for this, please tell me yhe better way to resolve this.</p>
