 Mirror

Pulling Digits Out of String to Sum Them (Views: 100)

 Problem/Question/Abstract:How do I pull out every second digit from a string and sum them?Answer:This is a rather unusual question, but it's not that hard to accomplish.What must iterate through each character of the string and "grab" the digits whose position is a multiple of two (2). There are a couple of ways to do this, but I took what I felt was the easier route. Since this is more or less a binary problem, setting a Boolean value with each iteration works nicely. Here's the logic:For all "odd" positions, set Boolean value to False;For all "even" positions, set Boolean value to True;If the Boolean value is true, grab that character and add it to a temporary buffer.Iterate through the buffer, and convert each character to an Integer while adding the converted value to an integer variable.Here's the code that accomplishes the above:function AddEvenOrOddChars(S: string; OddOrEven: Boolean): Integer;var  I: Integer;  evn: Boolean;  buf: string;begin  Result := 0;  {If OddOrEven was passed as True, then the all odd positions   will be grabbed and summed. If False, then all even positions   will be grabbed and summed.}  evn := EvenOdd;  {First grab the even position characters}  for I := 1 to Length(S) do  begin    if evn then      buf := buf + S[I];    {Set boolean to its opposite regardless of its current value.     If it's currently true, then we've just grabbed a character.     Setting it to False will make the program skip the next one.}    evn := not evn;  end;  {Now, iterate through the buffer variable to add up the individual   values}  for I := 1 to Length(buf) do    Result := Result + StrToInt(buf[I]);end;

<< Back to main page