Day 17: More Exceptions
Problem
Aim
Prior to this problem you learned to manage exceptional situations by using try and catch blocks. In today's challenge, you're going to practice throwing and propagating an exception.
Propagating Exceptions
If an exception is not caught by the method that threw it, the program's control is transferred back (propagated) to the calling method (i.e.: whatever called the method that threw the exception). This can be good if you have designed your program to handle exceptions at a high level, but bad if you never write code to catch the exception in the calling methods that the exception is being propagated to. The example method below throws an exception of type Exception, which propagates back to the calling method (main), where a catch block catches it and prints a message:
class PropagatedException {
void example() throws Exception{
throw new Exception("This exception will always be thrown.");
}
public static void main(String[] args) {
PropagatedException p = new PropagatedException();
try{
p.example();
}
catch(Exception e){
System.err.println( e.getClass().getSimpleName() + ": " + e.getMessage() );
}
}
}
The above code throws a java.lang.Exception and prints:
Exception: This exception will always be thrown.
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 n or p 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 Style
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 and 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
4
3 5
2 4
-1 -2
-1 3
Sample Output
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 , 3^5 which is 243 .
T1: 2 and 4 are positive, so power returns the result of 2^4=, 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.
Recommended: Please try your approach on your integrated development environment (IDE) first, before moving on to the solution.
Few words from CodingHumans : Don't Just copy paste the solution, try to analyze the problem and solve it without looking by taking the the solution as a hint or a reference . Your understanding of the solution matters.
HAPPY CODING 😁
Solution
( Java )
import java.util.*;
import java.io.*;
class Calculator {
public int power(int n,int p) throws Exception{
if(n<0 || p<0){
throw new Exception("n and p should be non-negative");
}
else{
return (int)Math.pow(n,p);
}
}
}
class Solution{
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int t = in.nextInt();
while (t-- > 0) {
int n = in.nextInt();
int p = in.nextInt();
Calculator myCalculator = new Calculator();
try {
int ans = myCalculator.power(n, p);
System.out.println(ans);
}
catch (Exception e) {
System.out.println(e.getMessage());
}
}
in.close();
}
}
If you have any doubts regarding this problem or need the solution in other programming languages then leave a comment down below .
