Question

1. (a) A class Scanner in Java can be used to get user input and its methods can be used after the following statement is executed:

        Scanner input = new Scanner(System.in);
   

   One of its methods nextDouble() returns the next double value from the keyboard. Now you are requested to write a method enterHeight() which displays the message "Input height: " and uses the method input.nextDouble() to get the user input. The process should be repeated until the input is non-negative. Finally the input should be returned. You can assume the aforementioned statement starting with Scanner has already been executed.

2. (b) Write a method category(double height) which returns a suitable type in string form according to the following:

Condition Type height >= 200 Tall

100 <= height < 200 Medium height < 100 Short

Answer 1

(a) method : enterHeight():-

Explanation: The method enterHeight() must read height as a double value and return it. so its return type should be double.

here we are using do-while loop, in that using scanner object we read input height as double and if it is negative value then input reading is iterated, whenever we have supplied non negative value then only loop will be terminated and height value will be returned to the calling method.

double enterHeight()
{
Scanner input=new Scanner(System.in);
double height;
   do
   {
   System.out.print("Input hegiht:");
   height=input.nextDouble();
   }while(height<0);
  
   return height;
}

(b) method : category(height)

explanation: this method must return the words either "Tall" or "Medium" or "Short". So its return type should be string.

the calling method passes height value. based on the value of the parameter height. the category() method return string.

if height >= 200 then the method returns the string "Tall"

other wise if the height >=100 and height<200 then it returns "Medium"

otherwise the method returns "Short".

String category(double height)
{
if(height>=200)
return "Tall";
else if(height>=100 && height<200)
return "Medium";
else
return "Short";
}

java Program using above methods:

import java.util.*;
class Height_Example
{
double enterHeight()
{
Scanner input=new Scanner(System.in);
double height;
   do
   {
   System.out.print("Input hegiht:");
   height=input.nextDouble();
   }while(height<0);
  
   return height;
}

String category(double height)
{
if(height>=200)
return "Tall";
else if(height>=100 && height<200)
return "Medium";
else
return "Short";
}

public static void main(String arg[])
{
Height_Example p=new Height_Example();
double height=p.enterHeight();
System.out.println(p.category(height));
}
}