for (String city : cityNTemps.keySet())

Week 3: Objects, files and exceptions/12. Coldest city

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+Write the method
+
+String coldestCity(HashMap<String, Double> temps)
+
+which takes as its parameter a hashmap where the keys are city names and the values are temperatures.
+Your task is to find and return the name of the city with the lowest temperature.
+
+
+Example method call:
+
+public static void main(String[] args){
+    HashMap<String, Double> temps = new HashMap<>();
+    temps.put("Turku", 0.5);
+    temps.put("Tampere", -5.25);
+    temps.put("Helsinki", -2.5);
+
+    System.out.println("Coldest city: " + coldestCity(temps));
+}
+
+Program outputs:
+Coldest city: Tampere
+
+
+
+=====================================
+
+
+
+
+
+
+
+import java.util.Random;
+import java.util.HashMap;
+
+public class Test{
+    public static void main(String[] args){
+        final Random r = new Random();
+        
+        for (int testi=1; testi<=3; testi++) {
+            System.out.println("Test " + testi);
+            String[] kaup = "Turku Helsinki Tampere Rovaniemi Oulu Kajaani Jyväskylä Pori Vaasa".split(" ");
+
+            HashMap<String, Double> lt = new HashMap<>();
+            double[] add = {0, 0.25, 0.5, 0.75};
+            
+            for (String kaupunki : kaup) {
+                double l = 25 - r.nextInt(50);
+                //'add' array of 4 floats are used here
+                // randomly select 0-3 idx
+                // then pick up the float value from the 'add' array
+                // and add to the 'l' temperature
+                l += add[r.nextInt(4)];     
+                
+                lt.put(kaupunki, l);
+            }
+            
+            System.out.println("Temperatures: ");
+            System.out.println("" + lt);
+            System.out.println("Coldest city: " + coldestCity(lt));
+            System.out.println("");
+        }
+    }
+    
+
+
+
+    public static String coldestCity(HashMap<String, Double> cityNTemps) {
+        String coldest = "";
+        double coldestTemp = 999;
+        for (String city : cityNTemps.keySet()) {
+            if (cityNTemps.get(city) < coldestTemp) {
+                coldest = city;
+                coldestTemp = cityNTemps.get(city);
+            }
+        }
+        return coldest;
+    }
+
+
+
+
+}
+
+
+    
+ 
+
+
+
+
+Test 1
+Temperatures: 
+{Pori=-8.0, Jyväskylä=14.0, Kajaani=-16.0, Oulu=-1.0, Helsinki=1.0, Rovaniemi=1.0, Turku=20.5, Tampere=0.0, Vaasa=-2.75}
+Coldest city: Kajaani
+
+Test 2
+Temperatures: 
+{Pori=-8.25, Jyväskylä=20.5, Kajaani=-21.0, Oulu=8.5, Helsinki=-4.5, Rovaniemi=-1.0, Turku=14.75, Tampere=12.75, Vaasa=1.0}
+Coldest city: Kajaani
+
+Test 3
+Temperatures: 
+{Pori=9.75, Jyväskylä=4.5, Kajaani=-11.5, Oulu=-10.25, Helsinki=-12.5, Rovaniemi=20.0, Turku=9.5, Tampere=-8.0, Vaasa=7.75}
+Coldest city: Helsinki
+
+
+
+
+
+
+
+
+
+