js实现r的n次方

let r = 2;
let n = 3;
let result = Math.pow(r, n);
console.log(result); // 输出 8

let r = 2;
let n = 3;
let result = r ** n;
console.log(result); // 输出 8

function power(r, n) {
    if (n === 0) return 1; // 任何数的0次方都是1
    let result = 1;
    for (let i = 0; i < n; i++) {
        result *= r;
    }
    return result;
}

let r = 2;
let n = 3;
console.log(power(r, n)); // 输出 8

function power(r, n) {
    if (n === 0) return 1;
    if (n < 0) return 1 / power(r, -n);
    return r * power(r, n - 1);
}

let r = 2;
let n = -3; // 负指数示例
console.log(power(r, n)); // 输出 0.125

function fastPower(r, n) {
    if (n === 0) return 1;
    let result = 1;
    while (n > 0) {
        if (n % 2 === 1) {
            result *= r;
        }
        r *= r;
        n = Math.floor(n / 2);
    }
    return result;
}

let r = 2;
let n = 10;
console.log(fastPower(r, n)); // 输出 1024