Answer:
You have specified no language. Here's an algorithm to follow with most platforms, my example is in NodeJS
const fs = require('fs');
let zone = fs.readFile('Zone.txt', 'utf8', function (err, data) {
if (err) throw new Error(err);
data = data.toString(); //convert the buffer to a string
let lines = data.split("\\"),
content = [];
for (i in lines) {
let l = lines[i];
if (l.toLowerCase().startsWith("a")) l = reverseString(l);
content.push(l);
}
content = content.join("");
fs.writeFile('zone1.txt', content, , function (err) {
if (err) throw new Error(err);
}
});
function reverseString (str) {
return str.split("").reverse().join("");
}