计算一个数的绝对值
function abs(x) {if (x >= 0) {return x;} else {return -x;}}console.log(abs(10) === abs(-10)); //=>true
计算数组元素之和
let arr = [1, 3, 5];function sum(array) {let sum = 0;for (let x of array) {//循环数组把每个元素赋给xsum += x;}return sum;}console.log(sum(arr));
计算阶乘(1)
function factorial(n) {let product = 1;//乘积初始化为1while (n > 1) {product *= n;n--;}return product;}console.log(factorial(4));//=> 24:1*4*3*2
计算阶乘(2)
function factorial2(n) {let product = 1;for (i = 2; i <= n; i++) {product *= i;}return product;}console.log(factorial2(4));//=>24:1*2*3*4