Thread: How to turn my If statement into a case/switch statement?

So from what iv learnt in Java and programming in general is that using a case statement is far more efficient that using multiple IF statements. I have an multiple IF statements contained within a method of my program, and would like to instead use a case statement. Unfortunately, i do not know how. Please, rather than just give me an example of random code; could you please adapt my example (even if only by a couple of lines), that way, it is much easier for me to understand as i already grasp the concept of this method that i am using.

 
public String checkPasswordStrength(String passw) 
    {
                int strengthCount=0;
                String strengthWord = "";
        String[] partialRegexChecks = { ".*[a-z]+.*", // lower
                                        ".*[A-Z]+.*", // upper
                                        ".*[\\d]+.*", // digits
                                        ".*[@#$%!]+.*" // symbols
        };
            if (passw.matches(partialRegexChecks[0])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[1])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[2])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[3])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.length()>7)
            {
                strengthCount+=1;
            }
 
            //StrengthCount Converted to string
 
            if (strengthCount==0)
            {
                strengthWord = "No password; da fuq hacks";
 
            }
 
            if (strengthCount==1)
            {
                strengthWord = "Very Weak";
 
            }
 
            if (strengthCount==2)
            {
                strengthWord = "Weak";
 
            }
 
            if (strengthCount==3)
            {
                strengthWord = "Medium";
 
            }
 
            if (strengthCount==4)
            {
                strengthWord = "Strong";
 
            }
 
            if (strengthCount==5)
            {
                strengthWord = "Very Strong";
 
            }
 
            return strengthWord;
    }

Please help me!

I'm not sure I agree with your premise in general, but I definitely can see from your code that not all 'if' statements can be converted to more efficient switch statements. If you can suggest how that might be done in this case, I'd be interested to hear it.

Ahhhh, being fairly new to programming i assumed that i could make this code more efficient. So is there no way this code can be made more efficient?

Kind Regards, Shaun

You could define an array of strength strings, like:

String[] strengthString = { "No password; da fuq hacks",
                                           "Very Weak",
                                           "Weak",
                                             . . . etc.

and then return the appropriate strengthString using the strengthCount:

return strengthString[strengthCount];

to eliminate the last 6 if statements.

Would it be possible to show me the full code of how to do this? I'm not too sure of how to code this properly - even with the example you have given. I would be very grateful!

By the way, switch-case statements can only be used for variables of type int, char or Enum's.
If-Then-Else blocks like these:

if (passw.matches(partialRegexChecks[0]))

Can not be made into a switch-case block.

But comparisons like these:

if (strengthCount==0)

can be.

An example would be:

switch (strengthCount){
  case 0:
    // do stuff
    break;
  case 1:
    // do other stuff
    break;
  ...
}

Originally Posted by blobby404

Would it be possible to show me the full code of how to do this? I'm not too sure of how to code this properly - even with the example you have given. I would be very grateful!

You try it and come back to ask for help with whatever problems you're having. I've shown you all but for ~3 lines of code.

Iv attempted this, and whilst it works to some degree; It is detecting Very strong passwords as strong, and strong passwords as meduim, etc. Help me please! Haha xD

Below is my case statement which i have created.

 
   switch (strengthCount){
            case 0:
            strengthWord = "No password; da fuq hacks";
             break;
            case 1:
            strengthWord = "Very Weak";
            break;
            case 2:
            strengthWord = "Very Weak";
            break;
            case 3:
            strengthWord = "Weak";
            break;
            case 4:
            strengthWord = "Medium";
            break;
            case 5:
            strengthWord = "Strong";
            break;
        }
            return strengthWord;

I have created an algorithm which checks a password for its strength. The program does this by checking for length of string, and types of charecters used.

I have created this method using mainly IF statements. I have tried to convert the IF statement into a Case statement; as this is more efficient. Although the Case statement still judges the strength of a password, it judges it wrong, judging very strong passwords as strong passwords, and strong passwords as meduim passwords etc.

Below is the code for my working program using IF statements, and the second batch of code is the code which contains the case statement.

 
     public String checkPasswordStrength(String passw) 
    {
            int strengthCount=0;
            String strengthWord = "";
    String[] partialRegexChecks = { ".*[a-z]+.*", // lower
                                    ".*[A-Z]+.*", // upper
                                    ".*[\\d]+.*", // digits
                                    ".*[@#$%!]+.*" // symbols
    };
        if (passw.matches(partialRegexChecks[0])) 
        {
                strengthCount+=1;
        }
 
        if (passw.matches(partialRegexChecks[1])) 
        {
                strengthCount+=1;
        }
 
        if (passw.matches(partialRegexChecks[2])) 
        {
                strengthCount+=1;
        }
 
        if (passw.matches(partialRegexChecks[3])) 
        {
                strengthCount+=1;
        }
 
        if (passw.length()>7)
        {
            strengthCount+=1;
        }
 
        //StrengthCount Converted to string
 
        if (strengthCount==0)
        {
            strengthWord = "No password; da fuq hacks";
 
        }
 
//ORIGINAL IF STATEMENT
 
        if (strengthCount==1)
        {
            strengthWord = "Very Weak";
 
        }
 
        if (strengthCount==2)
        {
            strengthWord = "Weak";
 
        }
 
        if (strengthCount==3)
        {
            strengthWord = "Medium";
 
        }
 
        if (strengthCount==4)
        {
            strengthWord = "Strong";
 
        }
 
        if (strengthCount==5)
        {
            strengthWord = "Very Strong";
 
        }
 
        return strengthWord;
}

Below is the complete code using the case statement.

 
   public String checkPasswordStrength(String passw) 
    {
                int strengthCount=0;
                String strengthWord = "";
        String[] partialRegexChecks = { ".*[a-z]+.*", // lower
                                        ".*[A-Z]+.*", // upper
                                        ".*[\\d]+.*", // digits
                                        ".*[@#$%!]+.*" // symbols
        };
            if (passw.matches(partialRegexChecks[0])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[1])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[2])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.matches(partialRegexChecks[3])) 
            {
                    strengthCount+=1;
            }
 
            if (passw.length()>7)
            {
                strengthCount+=1;
            }
 
            //StrengthCount Converted to string - CASE STATEMENT
 
            switch (strengthCount){
            case 0:
            strengthWord = "No password; da fuq hacks";
             break;
            case 1:
            strengthWord = "Very Weak";
            break;
            case 2:
            strengthWord = "Very Weak";
            break;
            case 3:
            strengthWord = "Weak";
            break;
            case 4:
            strengthWord = "Medium";
            break;
            case 5:
            strengthWord = "Strong";
            break;
        }
            return strengthWord;
    }

Any help would be greatly appreciated.

How is the switch statement more efficient than if/else?

It sounds like the result is one greater than you'd like, so check your logic. Can strengthCount ever be zero?

Because it uses less lines of code. And yes it can be zero, if no password exists then it is indeed zero. When a password which is an empty string is checked then the program still returns "no password" even with the case statement, so i cant understand why everything else is messing up. Please, i have had alook at the problem and cannot find a solution, im getting very frustrated with it and i know that's a big part of programming but i posted this thread for a solution, so please help!

Well according to the lessons that i have taken it is better to code with less lines. Iv already done this and they are not, i think it is a syntax error but i am unsure as i am unfamiliar with Java. If the general solution works fine with IF statements then why does the case statement not work! This is what i do not understand.

I can actually check the output perfectly fine, i have a Binary Tree which allows me to search users and test this. I know which passwords equal what strengths! Although i am only showing this method in my post i have created the rest of the program! I have posted a screenshot of this below.

passstr.jpg

1 Shaun Password1! memorable1
2 Andrew Password2 memorable2
3 Danny Password memorable3
4 Zac password memorable4
5 Lauren pass memorable5
6 Jake memorable6
7 Andy p7 memorable7
8 Chris Password£8 memorable8
9 Theo p!9 memorable9
10 Matthew password10 memorable10

USER FOUND
Search Results:

ID: 1
Name: Shaun
Password: Password1!
Password Strength: Strong
Enycrpted Password: !1drowssaP
Memorable Word: memorable1

No, because the output that the switch statment has been producing has been incorrect, whereas the IF statements was producing the correct results, which is why i cant figure out why it is not working

Iv found the error. I had repeated some strings in the switch statement multiple times. So actually output was correct, i had just repeated some strings by accident.

OLD VERSION OF CODE:

 
      //StrengthCount Converted to string - CASE STATEMENT
 
            switch (strengthCount){
            case 0:
            strengthWord = "No password; da fuq hacks";
             break;
            case 1:
            strengthWord = "Very Weak";
            break;
            case 2:
            strengthWord = "Very Weak";
            break;
            case 3:
            strengthWord = "Weak";
            break;
            case 4:
            strengthWord = "Medium";
            break;
            case 5:
            strengthWord = "Strong";
            break;
        }

NEW VERSION OF CODE:

 
 switch (strengthCount){
            case 0:
            strengthWord = "No password; da fuq hacks";
             break;
            case 1:
            strengthWord = "Very Weak";
            break;
            case 2:
            strengthWord = "Weak";
            break;
            case 3:
            strengthWord = "Medium";
            break;
            case 4:
            strengthWord = "Strong";
            break;
            case 5:
            strengthWord = "Very Strong";
            break;
        }

Thank you. Thank you to you and everyone else who gave advice.