Question

It was pointed out to me that the statement below is not recursion. I thought recursion only means that it calls itself until the answer is found. What would make this recursion?

public static double totalDistance(int[] x, int[] y, String[] city, int i){

    double xSub = x[i] - x[i-1];
    double ySub = y[i] - y[i-1];
    double distance = Math.pow(xSub, 2) + Math.pow(ySub, 2);
    distance = Math.round(Math.sqrt(distance));
    System.out.println("Distance From " + city[i] + " to " + city[i-1] + " is " + distance + " miles.");

   if (i == 1){
       return distance;  
   }
   else {
      return distance+totalDistance(x,y,city, i-1);
   }
}

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This is entire code below in case anyone is curious to what is going on…

import java.util.Scanner;
class distance {


public static void main(String[] args) {

    System.out.println("Welcome to Travel Bliss Distance Calculator!");
    Scanner input = new Scanner(System.in);
    int[] x = new int[5];
    int[] y = new int[5];
    String[] city = new String[5];


    int i=0;
    for (i=0; i < 5;i++){
        System.out.println("Enter City>>");
        city[i] = input.next();
        System.out.println("Enter X Coordinates>>");
        x[i] = input.nextInt();
        System.out.println("Enter Y Coordinates>>");
        y[i] = input.nextInt();
        System.out.println("You Entered: " + city[i] + " with Coordinates: (" + x[i] + "," + y[i] + ") ");


    }
    i = i-1;
    System.out.println("============================================================");

    System.out.println("Calculating Distance Between: " + city[0] +", " + city[1] + ", " + city[2] + ", " + city[3] + ", " + city[4]+" >>>");
    System.out.println("TOTAL of: "+ totalDistance(x, y, city, i)+ " miles.");

}


public static double totalDistance(int[] x, int[] y, String[] city, int i){

    double xSub = x[i] - x[i-1];
    double ySub = y[i] - y[i-1];
    double distance = Math.pow(xSub, 2) + Math.pow(ySub, 2);
    distance = Math.round(Math.sqrt(distance));
    System.out.println("Distance From " + city[i] + " to " + city[i-1] + " is " + distance + " miles.");

   if (i == 1){
       return distance;  
   }
   else {
      return distance+totalDistance(x,y,city, i-1);
   }
}
}

Answer 1

The totalDistance(…) function is indeed recursive (since it calls itself).