两个数的和

无形参

function fn() {
    let num1 = +prompt('请输入第一个数字');
    let num2 = +prompt('请输入第二个数字');
    let sum = num1 + num2;
    console.log(`最后的和是: ${sum}`);
}
fn();

有形参

function fn(a, b) {
    console.log(a + b);
}
fn(1, 2);
fn(4, 5);

计算总分

无形参

function getSum() {
    let ary = [89, 78, 23, 45, 66, 99];
    let sum1 = 0;
    for(let i = 0; i < ary.length; i++) {
        sum1 += ary[i];
    }
    console.log(`最后的结果是: ${sum1}`);
}
getSum();

优化（有形参）

function fn(ary) {
    let sum = 0;
    for(let i = 0; i <ary.length; i++) {
        sum += ary[i];
    }
    console.log(sum);
}
fn([100, 200]);
fn([100, 200, 300, 400, 500]);