Question

CS 209 Data Structure

2. Create a method that takes a HashMap and returns the sum of the keys of the HashMap.

3. Create a method that takes a HashMap and returns the sum of all keys and values of the HashMap.

For example, if the input is [1=9, 3=6, 4=9, 6=8, 7=6] then the method should return 59.

Answer 1

A method that takes a HashMap and returns the sum of the keys of the HashMap

public <K, V extends Number> double sumKeys(Map<K, V> map) {  
  // hashmap with data type of double and method written to get sum of keys 

    double sum = 0.0d;  // defination of sum
    for (Number key : map.key())  // take key in for loop
        sumkey += key.doubleValue();  // sum+ function will add up all the output given by for loop
    return sumkey; // returns sum of all key of HashMap
}

A method that takes a HashMap and returns the sum of all keys and values of the HashMap.

 Public sumKeyValue(Map<K, V> map)
 // method  to return the sum of key and values of Hashmap

 { 
  public <K, V extends Number> double sumKeys(Map<K, V> map) 
  // method that returns sum of keys
  {
    double sum = 0.0d;
    for (Number key : map.key()) // take key in for loop
        sumkey += key.doubleValue();
    return sumkey;
  }

public <K, V extends Number> double sumValues(Map<K, V> map) 
// method that returns sum of values
  {
    double sum = 0.0d;
    for (Number value : map.values()) // take value in for loop
        sumvalue += value.doubleValue();
    return sumvalue;
   }
   
   return sumkey+sumvalue; // returns total sum of keys and values
}