Replace wildcard text in file with specific text.

I have a file I need to open and find "0x.xx", where x.xx is a wildcard that is all numbers.
I need to replace "0x.xx" with "01.00". The "0x.xx" is more than "01.00". Could someone give me some code to do that and then output the entire file into a new file?

Cannot use string.

man awk
man sed

I'm currently using the following code to store the information I'm looking looking for in a variable, but I need to change it and reinsert it into the file. It's untested atm, but should work.

Code:

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FILE *fp = fopen ("/somepath/file.DAT", "r" ); 
        if ( fp != NULL )
        {       
                char line [ 16 ];
                if (fgets ( line, sizeof line, fp ) != NULL) {
                sprintf(Versioninfo, "%s", strstr(line, "0")+1+strstr(line, ".")+2+strstr(line, "00")); // 0x.xx00 (IE: 01.1300)
                return 0;
        } else {
                return -2;
    }
  } else {
    return -1;
  }

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Is this part of some automatic version numbering when building your software?

Quote:

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Originally Posted by Salem

Is this part of some automatic version numbering when building your software?

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no .