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import java.io.IOException;
import java.util.Scanner;
/**
*
* main()-|
* | parseNumber()--|
* | / |
* |-> performAction() -> calculateResult() <-------------|
* \ |
* parseNumber()--|
*
*/
public class Home {
public static int NaN = -989898;
public static void main(String[] args) {
performAction();
}
//runner method
private static void performAction() {
try {
String firstNum, secondNum;
System.out.println("This calculator takes input in form of numbers(one hundred) and performs divison");
System.out.println("Please enter the first number:");
Scanner input = new Scanner(System.in);
firstNum = input.nextLine();
System.out.println("Please enter the second number:");
secondNum = input.nextLine();
int result = calculateResult(firstNum.trim(), secondNum.trim());
if (result != NaN)
System.out.println(result);
} catch (IOException e) {
System.out.println(e.getMessage());
} finally {
input.close();
}
}
/**
* Performs divison operation on the provided input in the form of (firstNum / secondNum)
*
* @param firstNum
* @param secondNum
* @return the computed result
*/
private static int calculateResult(String firstNum, String secondNum) {
try {
int first = parseNumber(firstNum);
int second = parseNumber(secondNum);
return (first / second);
} catch (InvalidStringSequenceException e) {
System.out.println("\nEXCEPTION:---------Please enter valid numbers and try again.---------\n");
performAction();
} catch (ArithmeticException e) {
System.out.println("\nEXCEPTION:---------This is not possible mathematically.---------\n");
performAction();
}
return NaN;
}
/**
* Method to return the integer value of string sequence entered, else throw InvalidStringSequenceException
*
* @param num :: A string containing numbers in verbal format
* @return Integer value of the input string
* @throws InvalidStringSequenceException
*/
private static int parseNumber(String num) throws InvalidStringSequenceException {
if (num.equals("one hundred"))
return 100;
else if (num.equals("fifty"))
return 50;
else if (num.equals("zero"))
return 0;
else
throw new InvalidStringSequenceException("invalid string sequence");
}
}
// custom exception class
class InvalidStringSequenceException extends Exception {
public static final long serialVersionUID = 123123;
public InvalidStringSequenceException(String s) {
super(s);
}
}
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