Question

Write a recursive method body for the method whose contract is given below. Note that n is a restores-mode parameter. As an example, if n = 314, the method should return 1. You can only use the NaturalNumber kernel methods multiplyBy10, divideBy10, and isZero.

/**

* Reports the minimum (i.e., smallest) digit of n when it is

* written in ordinary decimal notation.

* ...

* @ensures

* minDigit = [the minimum digit of n]

*/

private static int minDigit(NaturalNumber n) {

// Write code for here.

}

Answer 1

public class Nat {
   
    private static int minDigit(NaturalNumber n){
        if(n.isZero())return 0; // checks if n is zero or not;
        int min = n.divideBy10(); // min stores the remainder when n is divided by 10 and updates  n = n/10
        int temp = minDigit(n);   // get the minimum digit for updated n i.e n/10
        if(temp < min){           // compare both digit and find the minimum;
            min = temp;
        }
        return min;    // return the minimum
    }
}