/**
* Swaps two characters in an array of characters using the XOR swap algorithm.
*
* This function demonstrates bitwise XOR swapping for educational purposes.
* In production TypeScript, array destructuring swapping:
* `[textArr[left], textArr[right]] = [textArr[right], textArr[left]]`
* is strongly preferred for readability and optimizer friendliness.
*
* @param textArr - Mutable array of single-character strings.
* @param left - Zero-based index of the first character.
* @param right - Zero-based index of the second character.
*/
function xorSwapCharacters(textArr: string[], left: number, right: number): void {
// Guard clause: check bounds and handle empty array
if (
textArr.length === 0 ||
left < 0 ||
left >= textArr.length ||
right < 0 ||
right >= textArr.length
) {
return;
}
// XOR swap fails if left === right because (x ^ x) evaluates to 0
if (left === right) {
return;
}
// Convert UTF-16 code units, apply bitwise XOR, and convert back to string
textArr[left] = String.fromCharCode(
textArr[left].charCodeAt(0) ^ textArr[right].charCodeAt(0)
);
textArr[right] = String.fromCharCode(
textArr[right].charCodeAt(0) ^ textArr[left].charCodeAt(0)
);
textArr[left] = String.fromCharCode(
textArr[left].charCodeAt(0) ^ textArr[right].charCodeAt(0)
);
}
function main(): void {
const original: string = "hello";
const textArr: string[] = Array.from(original);
console.log(`Before: ${textArr.join("")}`);
xorSwapCharacters(textArr, 1, 4);
const result: string = textArr.join("");
console.log(`After: ${result}`);
}
main();
/*
run:
Before: hello
After: holle
*/
