Question

So i need help with this program, This program is supposed to ask the user to input their weight on earth so I would put "140" then it would ask "enter planet name, Min, Max or all" and if the user typed in all it would display all the planets and your weight on them. Right now Im suck on the part where im required to do a switch statement with a linear search. Below this im going to put what the output should look like when complete.

.
import java.util.Scanner;
import java.util.Arrays;

jGRASP exec: java PlanetWeight Please enter a weight on Earth (0 to quit): 14 Please enter a planet name or Max, Min, All: all 5.46 12.74 14.00 5.32 40.18 18.48 13.02 17.22 Please enter a weight on Earth (0 to quit) 50 14.0 pounds: Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Please enter a planet name or Max, Min, All: max 50.0 pounds is maximum of 143.5 on Jupiter Please enter a weight on Earth (0 to quit): 100 Please enter a planet name or Max, Min, All: min 100.0 pounds is minimum of 38.0 on Mars Please enter a weight on Earth (0 to quit) 150 Please enter a planet name or Max, Min, All: jupiter 150.0 pounds is 430.5 on jupiter Please enter a weight on Earth (0 to quit): 0 jGRASP: operation complete.

public class PlanetWeight {
public static String[] planets = {"Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"};
public static double[] gravity = {0.39, 0.91, 1.00, 0.38, 2.87, 1.32, 0.93, 1.23};

public static int findByPlanet(String planet) {
for (int i = 0; i < planets.length; i++) {
if (planets[i].equalsIgnoreCase(planet)) {
return i;
}
}
return -1;
}

public static int findByGravity(double grvty) {
for (int i = 0; i < gravity.length; i++) {
if (gravity[i] == grvty) {
return i;
}
}
return -1;
}

public static double weightOnPlanet(double weight, int planet) {
return weight * gravity[planet];
}

public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.print("Enter your weight: ");
String planet = in.nextLine();
int index = findByGravity(grvty);
switch (planet)
{
case "Mercury": break;
case "Venus": break;
case "Earth": break;
case "Mars": break;
case "Jupiter": break;
case "Saturn": break;
case "Uranus": break;
case "Neptune": break;
default: break;
}
  
}
}

Answer 1

CODE:

import java.util.Scanner;
import java.util.Arrays;

public class PlanetWeight {
   public static String[] planets = {"Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"};
   public static double[] gravity = {0.39, 0.91, 1.00, 0.38, 2.87, 1.32, 0.93, 1.23};

   public static int findByPlanet(String planet) {
       for (int i = 0; i < planets.length; i++) {
           if (planets[i].equalsIgnoreCase(planet)) {
               return i;
           }
       }
       return -1;
   }

   public static int findByGravity(double grvty) {
       for (int i = 0; i < gravity.length; i++) {
           if (gravity[i] == grvty) {
               return i;
           }
       }
       return -1;
   }

   public static double weightOnPlanet(double weight, int planet) {
   return weight * gravity[planet];
   }

   public static void main(String[] args) {
       Scanner in = new Scanner(System.in);
       double weight;
       String opt="";
       System.out.print("Enter your weight on Earth(0 to quit): ");
       weight = in.nextDouble();     //taking weight from user
       in.nextLine();
       int planet,index;
       while(weight>0)
       {
           System.out.print("enter planet name, min, max or all: ");
           opt=in.nextLine();    //taking option from user
           switch (opt)
           {

               case "Mercury":
                   planet=findByPlanet("Mercury");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Mercury");
                   break;
               case "Venus":
                   planet=findByPlanet("Venus");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Venus");
                   break;
               case "Earth":
                   planet=findByPlanet("Earth");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Earth");
                   break;
               case "Mars":
                   planet=findByPlanet("Mars");
                   System.out.println(weight+"pounds is "+weightOnPlanet(weight,planet)+"on Mars");
                   break;
               case "Jupiter":
                   planet=findByPlanet("Jupiter");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Jupiter");
                   break;
               case "Saturn":
                   planet=findByPlanet("Saturn");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Saturn");
                   break;
               case "Uranus":
                   planet=findByPlanet("Uranus");
                   System.out.println(weight+" pounds is "+weightOnPlanet(weight,planet)+"on Uranus");
                   break;
               case "Neptune":
                   planet=findByPlanet("Neptune");
                   System.out.println(weight+"pounds is "+weightOnPlanet(weight,planet)+"on Neptune");
                   break;
               case "all":   //if user enters all then finding weights of all planets
                   for(int i=0;i<planets.length;i++)
                   {
                       planet=findByPlanet(planets[i]);
                       System.out.println(planets[i]+"\t"+weightOnPlanet(weight,planet));
                   }  
                   break;
               case "max":   //if user enters max
                   double max_gravity=gravity[0];
                   for(int i=0;i<gravity.length;i++)       //finding maximum gravity in gravity array
                   {
                       if(gravity[i]>max_gravity)
                       {
                           max_gravity=gravity[i];
                       }
                   }
                   index = findByGravity(max_gravity);
                   System.out.println(weight+" pounds is the maximum of "+weightOnPlanet(weight,index)+" on "+planets[index]);
                   break;
               case "min":   //if user enters min
                   double min_gravity=gravity[0];
                   for(int i=0;i<gravity.length;i++)    //finding minimum gravity in gravity array
                   {
                       if(gravity[i]<min_gravity)
                       {
                           min_gravity=gravity[i];
                       }
                   }
                   index = findByGravity(min_gravity);
                   System.out.println(weight+" pounds is the minimum of "+weightOnPlanet(weight,index)+" on "+planets[index]);
                   break;                              
               default:
                   break;
           }
           System.out.print("Enter your weight on Earth(0 to quit): ");
           weight = in.nextDouble();
           in.nextLine();
       }  

   }
}

OUTPUT:

Enter your weight on Earth(0 to quit): 14 enter planet name, min, max or all: al1 ercury 5.46 enus 12.74 Earth 14.0 Mars 5.32 Jupiter 40.18 Saturn 18.48 ranus 13.020000000000001 Neptune 17.22 Enter your weight on Earth(0 to quit): 50 enter planet name, min, max or all: max 50.0 pounds is the maximum of 143.5 on Jupiter Enter your weight on Earth(0 to quit): 100 enter planet name, min, max or all: mirn 100.0 pounds is the minimum of 38.0 on Mars Enter your weight on Earth(0 to quit): 150 enter planet name, min, max or all: Jupiter 150.0 pounds is 430.5on Jupiter Enter your weight on Earth(0 to quit): 0