CODEWITHSUNDEEP
javadictionarysum
merchantofam
merchantofam

Reputation: 37

Finding sum of values in map java

I am beginner to Java, so I am learning through experimentation. I wanted to create a class where it would take a type of ride as a String and number of riders as an Integer. I decided to use Map because it would allow me to keep together a ride type with its pertinent # of individuals.

//How many attendants in total
System.out.println("How many attendents today?: ");
int numberOfAttendents = Integer.parseInt(bf.readLine());
System.out.println("Total number of attendents: " + numberOfAttendents);

Map<String, Integer> typeOfRide = new HashMap<String, Integer>();
boolean run = true;
final String counterEnd = "stop";
while(run)
{
   System.out.println("What type of ride?: ");
   String nameOfType = bf.readLine();
   if(nameOfType.equalsIgnoreCase(counterEnd))
   {
      run = false;
   }
   else
   {
     System.out.println("Number of riders?: ");
     Integer numberPerType =    Integer.parseInt(bf.readLine());                
     typeOfRide.put(nameOfType, numberPerType);
    }   
 }

So the above part compiles with no problem. However when I try to add the number of riders per ride type, I am having some difficulty try to come up with a way. I understand the enhanced for loop I used is for arrays and not for map.

 //Adding individual entries of same ride
   for(Integer i: typeOfRide)
   {
      int sum = 0;
      System.out.println("Which ride type?: ");
      String typeNumber = bf.readLine();
      sum = sum + typeOfRide.get(typeNumber);
      System.out.println("Total number of riders per" + typeNumber + ":" + sum);
    }

So if y'all can suggest a method to get the sum, I would appreciate. Thanks!

Upvotes: 1

Views: 3060

Answers (2)

Simon Forsberg
Simon Forsberg

Reputation: 13351

typeOfRide is a Map, which does not implement iterable, which should give you a compilation error above.

For the loop, you will probably want to use either typeOfRide.entrySet(), typeOfRide.keySet() or typeOfRide.values()

In addition to vinodadhikary's answer about moving the int sum = 0; to above the for-loop, looping on this should solve it.

Upvotes: 1

vee
vee

Reputation: 38645

You are initializing sum inside the loop which causes the value of sum to be typeOfRide.get(typeNumber). Move the line int sum = 0; above the for loop.

Upvotes: 2

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