Question

Good day stack overflow.

I’m a noob in using regex and here is my problem – I need to check a password if it contains 4 consecutive characters. so far what I have just covered is regarding the digits. Here is my regex:

ascending digits – ^.?(?:0123|1234|2345|3456|4567|5678|6789).$

descending digits – ^.?(?:9876|8765|7654|6543|5432|4321|3210).$

This works only for the digits. I know this is already an overkill in regex so I dont want to do it with the letters. It will be waaay too overkill if I do that.

abcdblah //true because of abcd

helobcde //true because of bcde

dcbablah //true beacause of dcba

heloedcb //true because of edcb

Any help would be highly appreciated. Thanks stackoverflow.

Answer 1

here is an idea that doesn’t use regex:
all characters have an ansi value and usually consecutive. so abcd should have let’s say the following ansi values:64,65,66,67

pseudocode:

for (i=string.start;i<string.end-4;i++) {
   check=string.substring(i,4);
   c1=check.substring(0,1);
   c2=check.substring(1,1);
   c3=check.substring(2,1);
   c4=check.substring(3,1);
   if (c1.ansival==c2.ansival+1 && c2.ansival==c3.ansival+1 && c3.ansival==c4.ansival+1) {
      return false;
   } else {
      return true;
   }
}

also repeat in reverse order (c1.ansival+1==c2.ansival) for descending order