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Posted 22 Jul 2007

String Wildcard Matching (* and ?)

, 22 Jul 2007 CPOL
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A simple function to perform wildcard ( * ? ) string matching


I had a problem where I wanted to match a string against a pattern based on wild characters (* and ?). The function presented in this article is a simple one that does this matching. Here are some sample patterns:

  • sam*
  • sam*e
  • samp?e
  • s*p?e
  • etc.

Using the Code

The usage of the function is very simple. Just call the function with two arguments. The first one is the string to be compared with the pattern specified in the second argument. The function does not perform any error checking.



bool pattern_match(const char *str, const char *pattern) {
    enum State {
        Exact,      	// exact match

        Any,        	// ?

        AnyRepeat    	// *


    const char *s = str;
    const char *p = pattern;
    const char *q = 0;
    int state = 0;

    bool match = true;
    while (match && *p) {
        if (*p == '*') {
            state = AnyRepeat;
            q = p+1;
        } else if (*p == '?') state = Any;
        else state = Exact;

        if (*s == 0) break;

        switch (state) {
            case Exact:
                match = *s == *p;

            case Any:
                match = true;

            case AnyRepeat:
                match = true;

                if (*s == *q) p++;

    if (state == AnyRepeat) return (*s == *q);
    else if (state == Any) return (*s == *p);
    else return match && (*s == *p);


  • 22nd July, 2007: Initial post


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

M Shahid Shafiq
Pakistan Pakistan
No Biography provided

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Comments and Discussions

Generalbug find Pin
Sudhanshu Pratap Singh16-Sep-13 12:20
memberSudhanshu Pratap Singh16-Sep-13 12:20 
AnswerString wildcard matching (* and ?) Pin
tmowhrekf12-Mar-13 17:59
membertmowhrekf12-Mar-13 17:59 
GeneralRe: String wildcard matching (* and ?) Pin
azorius24-Mar-13 1:10
memberazorius24-Mar-13 1:10 
GeneralRe: String wildcard matching (* and ?) Pin
tmowhrekf24-Mar-13 2:32
membertmowhrekf24-Mar-13 2:32 
GeneralThanks Pin
BugMeNot ACCOUNT16-Jul-09 6:02
memberBugMeNot ACCOUNT16-Jul-09 6:02 
GeneralBuggy!!! Pin
mi-chi18-Jan-08 2:18
membermi-chi18-Jan-08 2:18 
Nice small and simple code.

However, the simple match abcbde with *bd* fails.

In the above case, the routine will find that the first "b" after the wildcard matches the source after the "a", but the following "d" in the patterh doesn't match the "c" from the source and returns false, although the sequence "bd" exists later in the string.

If one character fails in the "exact matching" routine after a wildcard, the routine should extend the wildcard and search the rest of the string and see whether the exact match comes later in the string.
GeneralRe: Buggy!!! Pin
PatrickHe11-Jun-08 13:57
memberPatrickHe11-Jun-08 13:57 
GeneralHelpful - thank you Pin
aface17-Aug-07 15:37
memberaface17-Aug-07 15:37 
GeneralRe: Helpful - thank you Pin
M Shahid Shafiq17-Aug-07 20:54
memberM Shahid Shafiq17-Aug-07 20:54 
GeneralThere was a similar article already Pin
Yuantu Huang23-Jul-07 0:56
memberYuantu Huang23-Jul-07 0:56 
GeneralRe: There was a similar article already Pin
Alexandre GRANVAUD23-Jul-07 21:24
memberAlexandre GRANVAUD23-Jul-07 21:24 
GeneralRe: There was a similar article already Pin
sssw285-Mar-11 21:20
membersssw285-Mar-11 21:20 

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