Day 17: More Exceptions

Objective

Yesterday’s challenge taught you to manage exceptional situations by using try and catch blocks. In today’s challenge, you’re going to practice throwing and propagating an exception. Check out the Tutorial tab for learning materials and an instructional video!

Task

Write a Calculator class with a single method: int power(int,int). The power method takes two integers, n and p, as parameters and returns the integer result of n^p. If either or is negative, then the method must throw an exception with the message: n and p should be non-negative.

Note: Do not use an access modifier (e.g.: public) in the declaration for your Calculator class.

Input Format

Input from stdin is handled for you by the locked stub code in your editor. The first line contains an integer, T, the number of test cases. Each of the T subsequent lines describes a test case in 2 space-separated integers denoting n and p, respectively.

Constraints

• No Test Case will result in overflow for correctly written code.

Output Format

Output to stdout is handled for you by the locked stub code in your editor. There are T lines of output, where each line contains the result of n^p as calculated by your Calculator class’ power method.

Sample Input

1
2
3
4
5

4
3 5
2 4
-1 -2
-1 3

Sample Output

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2
3
4

243
16
n and p should be non-negative
n and p should be non-negative

Explanation

T = 4
T₀: 3 and 5 are positive, so power returns the result of 3⁵, which is 243.

T₁: 2 and 4 are positive, so power returns the result of 2⁴=, which is 16.

T₂: Both inputs (-1 and -2) are negative, so power throws an exception and n and p should be non-negative is printed.

T₃: One of the inputs (-1) is negative, so power throws an exception and n and p should be non-negative is printed.

Solution

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/*
 * You can use the following pseudocode:
 *
 * `S` = read string from stdin.
 * try {
 *     `N` = numeric value of `S`.
 *     
 *     If `N` is `NaN` or `undefined`, then some exception must be thrown,
 *     you can write the following withtout using conditional statement:
 *     <condition to return true when `N` is `NaN` or `undefined`> && an_undefined_function_call()
 *
 *     print `N`
 * } catch (err) {
 *     print `Bad String`.
 * }
 */

//Write your code here
let Calculator = function () {
    this.power = function (n, p) {
        try {
            if (n >= 0 && p >= 0) {
                return n ** p;
            } else {
                throw 'n and p should be non-negative';
            }
        } catch (error) {
            return error;
        }
    }
}