Question

Write a method called writeNums that takes an integer n as a parameter and prints to the console the

first n integers starting with 1 in sequential order, separated by commas. For example, consider the

following calls:

writeNums(5);

System.out.println(); // to complete the line of output

writeNums(12);

System.out.println(); // to complete the line of output

These calls should produce the following output:

1, 2, 3, 4, 5

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Your method should throw an IllegalArgumentException if passed a value less than 1. Write a simple

main program to call the recursive method for the examples of 5 and 12 above.

Answer 1

public class Main {

public static void main(String[] args) {

writeNums(5);

System.out.println(); // to complete the line of output

writeNums(12);

System.out.println(); // to complete the line of output

}

public static void writeNums(int n) {

if (n < 1) {

throw new IllegalArgumentException("Input must be greater than or equal to 1");

} else if (n == 1) {

System.out.print("1");

} else {

writeNums(n - 1);

System.out.print(", " + n);

}

}

}

Step-by-step explanation: