Question

JAVA. Rolling a die 60,000 times with streams.

Modify the code below to capture the time before and after evaluating the stream pipeline (use package java.time which contains instant and duration). Then calculate the difference between the Instants to determine the total time. Use Instant's static method now to get the current time. To determine the difference between two Instants, use class Duration's static method between, which returns a Duration object containing the time difference. Duration provides methods like toMillis to return a duration in milliseconds. Use these timing techniques to time the original stream pipeline's operation, then do so again using class Random from package java.util, rather than SecureRandom.

package randomintstream;

import java.security.SecureRandom;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.time.LocalDateTime;

public class RandomIntStream {

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
SecureRandom random = new SecureRandom();
  
//roll a die 60,000 times and summarize the results
System.out.printf("%-6s%s%n", "Face", "Frequency");
random.ints(60_000_000, 1, 7)
.boxed()
.collect(Collectors.groupingBy(Function.identity(),
Collectors.counting()))
.forEach((face, frequency) ->
System.out.printf("%-6d%d%n", face, frequency));
}
  
}

Answer 1

Program

import java.security.SecureRandom;
import java.time.Duration;
import java.time.Instant;
import java.util.Random;
import java.util.function.Function;
import java.util.stream.Collectors;

public class KuchBhi {

   /**
   * @param args the command line arguments
   */
   public static void main(String[] args) {
       //SecureRandom random = new SecureRandom();
       Random random = new Random();
      
       Instant start = Instant.now();//Start instant
      
       //roll a die 60,000 times and summarize the results
       System.out.printf("%-6s%s%n", "Face", "Frequency");
       random.ints(10000, 1, 7).boxed().collect(Collectors.groupingBy(Function.identity(), Collectors.counting()))
               .forEach((face, frequency) -> System.out.printf("%-6d%d%n", face, frequency));
      
       Instant end = Instant.now();//End instant
      
       //calculating duration
       long timeElapsed = Duration.between(start, end).toMillis();
      
       System.out.println("Time Taken: "+timeElapsed+" milliseconds");
   }
}

Outputs

e Test、巴src 、申(default package) > Q KuchBhì ··; main(String[l) : void 1 import java.security.SecureRandom; 2 import java.time.Duration; 3 import java.time.Instant; 4 import java.util.function.Function; 5 import java.util.stream.Collectors; 7 public class KuchBhi f 10 @param args the command 1ine arguments 12 public static void main(String[] args) 13 14 15 16 17 18 SecureRandom random new SecureRandom(); Instant startInstant.now();//Start instant //roll a die 60,000 times and summarize the results System.out.printf(%-6s%sn", "Face", "Frequency") random.ints (18800, 1, 7).boxed().collect(Collectors.groupingBy (Function.identity), Collectors.counting())) forEach( (face, frequency) -> System.out.printf("%-6d%0%n", face, frequency)); 21 Instant endInstant.now);//End instant //calculating duration long timeElapsed-Duration.between(start, end).toMillis); Console X 25 26 27 28 29 terminated> KuchBhi (1 cetion C ram FilesUava ire1.8.0 181bin exe (15-Apr-2019, 1:17:02 P System.out.println("Time Taken: "+timeElapsed+" milliseconds") Face Frequency 1782 1690 1726 1642 1651 Time Taken: 526 milliseconds

1 import java.security SecureRandom; 2 import java.time.Duration; 3 import java.time.Instant; 4 import java.util.Random 5 import java.util.function.Function; 6 import java.util.stream.Collectors; 8 public class KuchBhi t 1e 11 12 13 param args the command line arguments public static void main(String[] args) [ //SecureRandom random-new SecureRandom) Random random new Random) Instant startInstant.now);//Start instant 20 21 //roll a die 60,000 times and summarize the results System.out.printf("%-6sXs%n", "Face", "Frequency"); random.ints (10000, 1, 7).boxed().collect (Collectors.groupingBy (Fu forEach(face, frequency)-> System . out .printf("%-60%d%n", e D Console 3 terminated> KuchBhi (1) [Java Application) C:Program Files Javaljre1.8.0 181\binjavaw.exe (15-Apr-2019, 1:18:07 PM) 23 24 Instant endInstant.now);//End instant //calculating duration long timeElapsedDuration.between (start, end).toMillis; Face Frequency 1581 1757 1724 1666 1643 1629 2 29 System.out.printin(Time Taken: +timeElapsed+" milliseconds"); 31 Time Taken: 253 milliseconds

Test ig src (default package. Q KuchBhi 1 import java.security.SecureRandom; 2 import java.time.Duration; 3 import java.time.Instant; 4 import java.util.Random; 5 import java.util.function.Function; 6 import java.util.stream.Collectors; G' main(String(): void 8 public class KuchBhi t Le *@param args the command line arguments 13 public static void main(Stringl] args) 14 //SecureRandom random new SecureRandom); Random random = new Random()| Instant start -Instant.now);//Start instant //roll a die 6e,800 times and summarize the results System.out.printf("%-6sXs%n", "Face", "Frequency"); random.ints (18088, 1, 7).boxed().collect (Collectors.groupingBy(Function.identity(), Collectors.counting))) 20 forEach(face, frequency) -> System . out . printf("%-60%d%n", face, frequency)); 24 Instant endInstant.now);//End instant 26 27 /Icalculating duration long timeElapsed Duration.between (start, end).toMillis; 貝Console X terminated> KuchBhi (1) [Java Application] CAProgram FilesJavaljre1.8.0 181\bin javaw.exe (15-Apr-2019, 1:18:38 PM) System.out.println("Time Taken: "+timeElapsed+ milliseconds") Face Frequency 1633 1657 1697 1646 1706 1661 0 Time Taken: 114 milliseconds