# Ekuam-Mumin's solution

## to Wordy in the Java Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

#### Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Parse and evaluate simple math word problems returning the answer as an integer.

## Iteration 1 — Addition

Add two numbers together.

What is 5 plus 13?

Evaluates to 18.

Handle large numbers and negative numbers.

## Iteration 2 — Subtraction, Multiplication and Division

Now, perform the other three operations.

What is 7 minus 5?

2

What is 6 multiplied by 4?

24

What is 25 divided by 5?

5

## Iteration 3 — Multiple Operations

Handle a set of operations, in sequence.

Since these are verbal word problems, evaluate the expression from left-to-right, ignoring the typical order of operations.

What is 5 plus 13 plus 6?

24

What is 3 plus 2 multiplied by 3?

15 (i.e. not 9)

## Bonus — Exponentials

If you'd like, handle exponentials.

What is 2 raised to the 5th power?

32

# Running the tests

You can run all the tests for an exercise by entering

``````\$ gradle test
``````

## Source

Inspired by one of the generated questions in the Extreme Startup game. https://github.com/rchatley/extreme_startup

## Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

### WordProblemSolverTest.java

``````import org.junit.Ignore;
import org.junit.Rule;
import org.junit.Test;
import org.junit.Before;
import org.junit.rules.ExpectedException;

import static org.junit.Assert.assertEquals;

public class WordProblemSolverTest {

@Rule
public ExpectedException expectedException = ExpectedException.none();

WordProblemSolver solver;

@Before
public void setup() {
solver = new WordProblemSolver();
}

@Test
public void testSingleAddition1() {
assertEquals(2, solver.solve("What is 1 plus 1?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleAddition2() {
assertEquals(55, solver.solve("What is 53 plus 2?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleAdditionWithNegativeNumbers() {
assertEquals(-11, solver.solve("What is -1 plus -10?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleAdditionOfLargeNumbers() {
assertEquals(45801, solver.solve("What is 123 plus 45678?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleSubtraction() {
assertEquals(16, solver.solve("What is 4 minus -12?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleMultiplication() {
assertEquals(-75, solver.solve("What is -3 multiplied by 25?"));
}

@Ignore("Remove to run test")
@Test
public void testSingleDivision() {
assertEquals(-11, solver.solve("What is 33 divided by -3?"));
}

@Ignore("Remove to run test")
@Test
public void testMultipleAdditions() {
assertEquals(3, solver.solve("What is 1 plus 1 plus 1?"));
}

@Ignore("Remove to run test")
@Test
public void testAdditionThenSubtraction() {
assertEquals(8, solver.solve("What is 1 plus 5 minus -2?"));
}

@Ignore("Remove to run test")
@Test
public void testMultipleSubtractions() {
assertEquals(3, solver.solve("What is 20 minus 4 minus 13?"));
}

@Ignore("Remove to run test")
@Test
public void testSubtractionThenAddition() {
assertEquals(14, solver.solve("What is 17 minus 6 plus 3?"));
}

@Ignore("Remove to run test")
@Test
public void testMultipleMultiplications() {
assertEquals(-12, solver.solve("What is 2 multiplied by -2 multiplied by 3?"));
}

@Ignore("Remove to run test")
@Test
public void testAdditionThenMultiplication() {
assertEquals(-8, solver.solve("What is -3 plus 7 multiplied by -2?"));
}

@Ignore("Remove to run test")
@Test
public void testMultipleDivisions() {
assertEquals(2, solver.solve("What is -12 divided by 2 divided by -3?"));
}

@Ignore("Remove to run test")
@Test
public void testUnknownOperation() {
expectedException.expect(IllegalArgumentException.class);
expectedException.expectMessage("I'm sorry, I don't understand the question!");

solver.solve("What is 52 cubed?");
}

@Ignore("Remove to run test")
@Test
public void testInvalidQuestionFormat() {
expectedException.expect(IllegalArgumentException.class);
expectedException.expectMessage("I'm sorry, I don't understand the question!");

// See https://en.wikipedia.org/wiki/President_of_the_United_States if you really need to know!
solver.solve("Who is the President of the United States?");
}

}``````
``````import java.util.*;
import java.util.regex.*;

class WordProblemSolver
{
public int solve(String input)
{
if(!input.matches("^What is "+"([-]+[0-9]+|[0-9]+)"+"( "+"(plus|minus|multiplied by|divided by)"+" "+"([-]+[0-9]+|[0-9]+)"+")+"+"\\?"))
{
throw new IllegalArgumentException("I'm sorry, I don't understand the question!");
}

Matcher numbers = Pattern.compile("[-]+[0-9]+|[0-9]+").matcher(input);
Matcher operators = Pattern.compile("(plus|minus|multiplied by|divided by)").matcher(input);

numbers.find();
int total = Integer.valueOf(numbers.group(0));

while(numbers.find() && operators.find())
{
total = calculator(total, numbers.group(), operators.group());
}
}

private int calculator(int count, String number, String operator)
{
int result = 0;
switch(operator)
{
case "plus":
result = count + Integer.valueOf(number);
break;

case "minus":
result = count - Integer.valueOf(number);
break;

case "multiplied by":
result = count * Integer.valueOf(number);
break;

case "divided by":
result = count / Integer.valueOf(number);
break;
}
return result;
}
}``````