How to make user input in java be of the type double?

Question

This line:

arr[i] = sc.nextDouble();

from this code:

public class z01 { 
  public static void main(String[] args) { 
    @SuppressWarnings("resource") 
    Scanner sc = new Scanner(System.in); 
    System.out.println("Enter array size: "); 
    int n = sc.nextInt(); 
    double[] arr = new double[n]; 
    double min = 0; 
    for(double i = 0; i <n; i++){ 
      System.out.println("Enter element " + (i + 1)); 
      arr[i] = sc.nextDouble(); 
      if(i%3 == 0 && i <= min){ 
        min = i; 
      } 
    } 
    if(min != 0){ 
      System.out.println("The smallest number divisible by 3 is" + min); 
    } else { 
      System.out.println("No number is divisible by 3"); 
    } 
  } 
}

Gives this warning:

Type mismatch: cannot convert from double to int

How do I make user input in java be of the type double?

George Karanikas · Accepted Answer · 2012-08-05 23:17:33Z

3

~~Your problem here is probably that the array arr is of type int. That is why you get that error. Define arr as follows and try again (where x the desired dimension):~~

~~double arr[] = new double[x];~~

The problem is that you have set i in the for loop to be of type double while it should be of type int

edited Aug 5, 2012 at 23:17

answered Aug 5, 2012 at 22:53

George Karanikas

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5 Comments

George Karanikas Over a year ago

Then maybe perhaps i is double? Please give more information then.

user1577976 Over a year ago

public class z01 { public static void main(String[] args) { @SuppressWarnings("resource") Scanner sc = new Scanner(System.in); System.out.println("Enter array size: "); int n = sc.nextInt(); double[] arr = new double[n]; double min = 0; for(double i = 0; i <n; i++){ System.out.println("Enter element " + (i + 1)); arr[i] = sc.nextDouble(); if(i%3 == 0 && i <= min){ min = i; } } if(min != 0){ System.out.println("The smallest number divisible by 3 is" + min); } else{ System.out.println("No number is divisible by 3"); } } }

George Karanikas Over a year ago

As I said you have i declared as double. Make it int.

George Karanikas Over a year ago

change for(double i = 0; i <n; i++) to for(int i = 0; i <n; i++)

George Karanikas Over a year ago

Because array indexes have to be integers. You cannot access for example the 1.5 cell of an array because it doesn't exist.

DMor · Accepted Answer · 2012-08-05 22:54:30Z

0

One method is to use a try catch exception.

try {
     double var = sc.nextDouble();
} 
catch(TypeMismatchException ex) {
     System.err.println("try again, wrong type");
}

basically, if there is an error storing the value in a double, it'll execute the catch statement, and you can prompt the user again for more input.

answered Aug 5, 2012 at 22:54

DMor

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2 Comments

user1577976 Over a year ago

tried it, but it gives the same warning plus one more ( TypeMismatchException cannot be resolved to a type)

DMor Over a year ago

Then use Exception, because i'm not sure the specific one.

Quetzalcoatl · Accepted Answer · 2012-08-06 10:33:09Z

0

I noticed the following errors within your code:

You are using a double i in your for-loop for being the array index, when you read in the array index to int n. That's where your Type Mismatch error is coming from. As array indexes must be of the type int, the arr[i] you have is attempting to pass an arr[double] where only arr[int] is supported.
Your min needs to start at Double.MAX_VALUE if you want it to ever be re-assigned with the new minimum, unless you all entered values will be negative. Be sure to change your if (min != 0) { accordingly.

answered Aug 6, 2012 at 10:33

Quetzalcoatl

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