Question

question in java programming :

Suppose that you are an instructor and want to create a table that contains a list of students and their marks, like the following: Ahmad 80 7 Khalid Mohammed 91 Adil 66 74 Saeed Yousef 78 Omar 85 Salim Write a program that will store this information in a map and print all its members.

Answer 1

/**
* The java program that stores the student names
* marks in a Map and prints the names and marks
* on console output.
* */
//MapDriver.java
import java.util.HashMap;
import java.util.Map;
public class MapDriver
{
  
   public static void main(String[] args)
   {
      
       //Create an instance of HashMap object with key as string and value as integer
       //to store student name as key and marks as integer
       //Note : Since Map is a interface ,must implement a class HashMap
       //concrete class to use.
       //Java api already implmented HashMap class for Map interface
       Map<String,Integer> studentMap =
               new HashMap<String,Integer>();
      
      
      
      
      
       // Add students in the given table to the studentMap
       studentMap.put("Ahmed", 80);
       studentMap.put("Khalid", 72);
       studentMap.put("Mohammed", 91);
       studentMap.put("Adil", 66);
       studentMap.put("Saeed", 74);
       studentMap.put("Yousef", 62);
       studentMap.put("Omar", 78);
       studentMap.put("Salim", 85);
      
       //print heading for the student table
       System.out.printf("%-15s%-5s \n","STUDENT NAME","MARKS");
      
       // Iterate over all studentMap, using the keySet method.
       //Get a keySet over the student names and get the value associated with
       //name key using get function on studentMap object.
       for(String key: studentMap.keySet())
           System.out.printf("%-15s%-5d \n",key ,studentMap.get(key));
      
       //print the total students in the studnetMap object
       System.out.println("Student Count: " + studentMap.size());
      
   }
}//end of class

sample output:

STUDENT NAME   MARKS
Yousef         62  
Adil           66  
Ahmed          80  
Omar           78  
Salim          85  
Saeed          74  
Mohammed       91  
Khalid         72  
Student Count: 8

Hope this helps you