function a(text) {
    alert(text)
}

function cube(n) {
    return Math.pow(n, 3)
}

function avg2(a, b) {
    return (a + b) / 2
}

function sum3(a, b, ...c) {
    return a + b + +c
}
function intRandom(min = 0, max = 10) {
    return Math.round(Math.random() * (max - min - 1) + min)
}

function greetAll(...arguments) {
    for(let arg of arguments) {
        alert(`Hello, ${arg}!`)
    }
}
function sum(...arguments) {
    let result = 0
    for(let num of arguments) {
        result += num
    }
    return result
}

var sample = prompt("Введите название задания")

switch (sample.toLowerCase()){
    case "a": a('Test prompt')
        break
    case "cube": cube(5)
        break
    case 'avg2': avg2(55, 17)
        break
    case 'sum3': sum3(5, 82, 47)
        break
    case 'intRandom': intRandom(1, 105)
        break
    case 'greetAll': greetAll('Sonya', 'Kerry', 'Eve')
        break
    case 'sum': sum(45, 741, 32, 14)
        break
    default:
        a()
}

let sampleObj = {
        a: a(),
        cube: cube(),
        avg2: avg2(),
        sum3: sum3(),
        intRandom: intRandom(),
        greetAll: greetAll(),
        sum: sum(),
    };

console.log(sampleObj[prompt("Введите название задания")]);