# How to Find the Integral using Java ## The challenge

Create a function that finds the integral of the expression passed.

In order to find the integral all you need to do is add one to the `exponent` (the second argument), and divide the `coefficient` (the first argument) by that new number.

For example for `3x^2`, the integral would be `1x^3`: we added 1 to the exponent, and divided the coefficient by that new number).

Notes:

• The output should be a string.
• The coefficient and exponent is always a positive integer.

### Examples

``` 3, 2  -->  "1x^3"
12, 5  -->  "2x^6"
20, 1  -->  "10x^2"
40, 3  -->  "10x^4"
90, 2  -->  "30x^3"
```

## The solution in Java code

```public class Solution {

public static String integrate(int coefficient, int exponent) {
int first = ++exponent;
coefficient /= first;

return coefficient+"x^"+first;
}

}
```

A single line solution:

```public class Solution {

public static String integrate(int coefficient, int exponent) {
return coefficient / ++exponent + "x^" + exponent;
}

}
```

A solution using `String.format()`:

```class Solution {

static String integrate(int coefficient, int exponent) {
return String.format("%sx^%s", coefficient / ++exponent, exponent);
}

}
```

## Test cases to validate our Java solution code

```import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

public class SolutionTest {
@Test
public void exampleTests() {
assertEquals("1x^3", Solution.integrate(3,2));
assertEquals("2x^6", Solution.integrate(12,5));
assertEquals("10x^2", Solution.integrate(20,1));
assertEquals("10x^4", Solution.integrate(40,3));
assertEquals("30x^3", Solution.integrate(90,2));
}
}
```
Tags:
5 1 vote
Article Rating
Subscribe
Notify of 