? : once or not at all

you can use metacharacter ? To match a character once or not at all.

For Example 'threat' 'treat' are same except that one has a h and the other doesn't, we can use 'th?reat' to match both. 

Sample Output

Enter Regular Expression

th?reat

Enter the string

treat threat

I found the text treat starting at index 0 Ending at index 5

I found the text threat starting at index 6 Ending at index 12

               

another example, some will type August, some will type Aug. Now we can match both using 'Aug(ust)?'.

Enter Regular Expression

Aug(ust)?

Enter the string

I can type Aug or August my regx match both

I found the text Aug starting at index 11 Ending at index 14

I found the text August starting at index 18 Ending at index 24

Note

Use this program to run above sample

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