So I created a .js file to calculate the area of a circle and calculateArea() needs to calculate it. The only thing that it does is the prompt(). What am I doing wrong?

function calculateArea(myRadius){
  var area = (myRadius * myRadius * Math.PI);
  return area;

  function MyArea(){
    calculateArea(myRadius);
    alert("A circle with a " + myRadius + 
          "centimeter radius has an area of " + area + 
          "centimeters. <br>" + myRadius + 
          "represents the number entered by the user <br>" + area +
          "represents circle area based on the user input.");  
  }      
}
var myRadius = parseFloat(prompt("Enter the radius of your circle in cm:",0));
calculateArea(myRadius);

So I created a .js file to calculate the area of a circle and calculateArea() needs to calculate it. The only thing that it does is the prompt(). What am I doing wrong?

function calculateArea(myRadius){
  var area = (myRadius * myRadius * Math.PI);
  return area;

  function MyArea(){
    calculateArea(myRadius);
    alert("A circle with a " + myRadius + 
          "centimeter radius has an area of " + area + 
          "centimeters. <br>" + myRadius + 
          "represents the number entered by the user <br>" + area +
          "represents circle area based on the user input.");  
  }      
}
var myRadius = parseFloat(prompt("Enter the radius of your circle in cm:",0));
calculateArea(myRadius);

• javascript
• area

• *Not calling function MyArea, You need to revisit function calculateArea . – Ajay Narain Mathur Commented Sep 23, 2017 at 1:18
• As an aside, area is not measured in centimetres. (Your alert should probably say "square centimetres".) – nnnnnn Commented Sep 23, 2017 at 1:28

4 Answers 4

You need to keep function MyArea outside calculateArea and call calculateArea from within MyArea.

Call MyArea function instead of calculateArea.

Example Snippet:

function calculateArea(myRadius) {
  return (myRadius * myRadius * Math.PI);
}

function MyArea() {
  var area = calculateArea(myRadius);
  alert("A circle with a " + myRadius + "centimeter radius has an area of " + area + "centimeters. <br>" + myRadius + "represents the number entered by the user <br>" + area + "represents circle area based on the user input.");


}

var myRadius = parseFloat(prompt("Enter the radius of your circle in cm:", 0));
MyArea(myRadius);

PS: There are better ways to do this. Comment in case of questions.

this is a way for calculate the circle area

let Area, Environment;
let Radius = prompt("Enter Radius ");

function calculate(Radius) {
  CalEnvironment(Radius);
  CalArea(Radius);
}
function CalEnvironment(Radius) {
  Environment = Radius * 3.14 * 2;
  console.log("Environment is : " + Environment);
}
function CalArea(Radius) {
  Area = Radius * Radius * 3.14;
  console.log("Area is : " + Area);
}
calculate(Radius);

You basically need to call MyArea outside of calculateArea but in this case, why not something like this?

function calculateArea(myRadius) {
    return myRadius * myRadius * Math.PI;
}

var myRadius = parseFloat(prompt("Enter the radius of your circle in cm:",0));
var area = calculateArea(myRadius);

alert("A circle with a " + myRadius + "centimeter radius has an area of " + area + "centimeters. <br>" + myRadius + "represents the number entered by the user <br>" + area + "represents circle area based on the user input.");

The following is a single function solution:

function MyArea(myRadius){

	var area = Math.pow(myRadius, 2) * Math.PI;
  
	alert(
	    "A circle with a " + myRadius +
	    "centimeter radius has an area of " +
	    area + "centimeters. \n" + myRadius +
	    "represents the number entered by the user \n" +
	    area + "represents circle area based on the user input."
	);
}

var myRadius = parseFloat(prompt("Enter the radius of your circle in cm:", 0));

MyArea(myRadius);