学习避免使用 static 方法/变量。 制作返回数字的非静态方法时遇到问题

Question

I want to try practicing avoiding using static methods/variables when not needed, because I've heard/seen/been told that you want to avoid using them when you can. I decided to make a simple password cracker in Java:

import java.util.Random;
public class PasswordCracker 
{
    
    public static void main(String args[]) 
    {
        PasswordCracker pwcSimulation = new PasswordCracker();
        long totalTimeSpentCracking = 0;
        
        int numSimulations = 100;
        
        for(int i = 0; i < numSimulations; i++)
        {
            System.out.println(pwcSimulation.PasswordCrackingSimulation());
        }
        
    }
    
    long PasswordCrackingSimulation()
    {
        long startTime = System.currentTimeMillis();
        int upperBound = 999999;
        
        Random rand = new Random();
        int randomPassword = rand.nextInt(upperBound);
    
        int passwordGuess;
        for(int i = 0; i <= upperBound; i++)
        {
            passwordGuess = i;
            if(passwordGuess == randomPassword)
            {
                System.out.println("password Guessed correctly, the password was: " + randomPassword);
                break;
            }
            /*else
            {
                System.out.println("Your inputted password is incorrect, please try again.");
            }*/
        }
        long endTime = System.currentTimeMillis();
        long timeSpentCracking = (endTime - startTime);
        System.out.println("The program took " + timeSpentCracking + "ms OR ~" + ((timeSpentCracking/1000) % 60) + " seconds to complete");
        return timeSpentCracking;
    }
}

first instantiated a new class (hopefully i did this they way you should ?) to avoid having to use a static method for the method PasswordCrackingSimulation. Now i'm having trouble returning a value from the method. The printline in the loop will always print 0, so I know that it isn't taking the returned value in the method. Any help would be lovely:) just trying to learn

Answer 1

No, you're doing everything correctly.

You're returning how long it takes in milliseconds to crack that password.

The answer is less than 1 millisecond. That 0 you see? That's because your method is returning 0. It is doing that because endTime - startTime is zero .

Just write return 1 to test this out yourself - you'll see your print loop print 1 instead.