字符串操作

Question

如何查一个字符串中含有几个'a'????
用什么函数呢?

Answer 1

{ 2002.8.5 Kingron                 }
{ Source:Source string             }
{ Sub:Sub string                   }
{ Return:Count                     }
{ Ex:StrSubCount('abcdbcd','bc')=2 }
function StrSubCount(const Source, Sub: string): integer;
var
  Buf               : string;
  i                 : integer;
  Len               : integer;
begin
  Result := 0;
  Buf:=Source;
  i := Pos(Sub, Buf);
  Len := Length(Sub);
  while i <> 0 do
  begin
    Inc(Result);
    Delete(Buf, 1, i + Len -1);
    i:=Pos(Sub,Buf);
  end;
end; { StrSubCount }

Answer 2

function CountChar(TheStr:String;TheChar:Char):Integer;
  var
    iTmp:Integer;
    iPos:Integer;
  begin
    iTmp:=0;
    for iPos:=Length(TheStr) downto 1 do
      if TheStr[iPos]=TheChar then
        iTmp:=iTmp+1;
    Result:=iTmp;
  end;

Answer 3

showmessage( inttostr( CountChar( 'abcadfcab','a' ) ) );