javascript - 尝试编写一个javascript程序来计算球体的体积

Question

    // sphere.js #2
// This script calculates the volume of a sphere.

// Function called when the form is submitted.
// Function performs the calculation and returns false.
function calculate() {
    'use strict';

    // For storing the volume:
    var volume;

    // Task 1: Get a reference to the form element:
    var radius = document.getElementById("radius");

    // Add an "if" statement here to
    // make sure there is a reference
    if (radius) {
        //Task #2: Add an "if" to make sure the value is positive:
        if (radius > 0) {
            // Task #3: Perform the calculation:
            volume = (4/3)*(22/7)*(Pow(radius,3));
            //HINT: the formula for the volume of a sphere is V=(4/3)*(pi)*(radius cubed)

            // Format the volume:
            volume = volume.toFixed(4);

            // Task #4: Display the volume:
            document.getElementById("volume").id ="volume";
            //Hint: use the same method as in the radius variable assignment call above
        } //End if 
    } end if radius

    // Return false to prevent submission:
    return false;

} // End of calculate() function.

// Function called when the window has been loaded.
// Function needs to add an event listener to the form.
function init() {
    'use strict';
    document.getElementById('theForm').onsubmit = calculate;
} // End of init() function.
window.onload = init;

我正在尝试编写一个脚本来计算球体的体积。这是一项家庭作业，所以这就是为什么所有这些评论都在那里。它基本上告诉我该怎么做。

嗯，我尽我所知遵循了它，但我仍然收到错误。我得到的错误是第 30 行上的“SyntaxError: Missing ; before statements”。这告诉我要放一个 ;在“结束如果”之前。我猜这不是错误。我猜公式是错误的。

Answer 1

这是计算球体体积的公式:

考虑到这一点，

function volumeOfSphere(radius) {
    return (4/3)*Math.PI*Math.pow(radius,3);
}

console.log('The volume of a sphere with a radius of 5 is: '+volumeOfSphere(5));

此外，请不要使用 22/7 作为 pi 的估计值，请使用 Math.PI

另一方面，您的代码无法正常工作的原因是 end if 不是 javascript 代码。您应该删除它，然后重新测试您的代码。

这是一个工作 fiddle :https://jsfiddle.net/qm6uaapu/