typedef enum
{
    CFM_Superscript, // 上标
    CFM_Subscript,   // 下标
    CFM_Normal       // 普通文本
}TCharacterFormat;

void MySetCharFormat(TRichEdit *RichEdit, TCharacterFormat CharacterFormat)
{
    // ccrun(老妖)根据Delphi超级猛料中的资料修改而成

    // 欢迎光临 C++ Builder 研究 http://www.ccrun.com
    TCharFormat Format;
    Format.cbSize = sizeof(Format);
    Format.dwMask = CFM_OFFSET;
    // Character offset, in twips, from the baseline.
    // If the value of this member is positive,
    // the character is a superscript;
    // if it is negative, the character is a subscript.
    switch(CharacterFormat)
    {
        case CFM_Superscript:
            Format.yOffset = 60;
            break;
        case CFM_Subscript:
            Format.yOffset = -60;
            break;
        case CFM_Normal:
            Format.yOffset = 0;
            break;
        default:
            break;
    }
    // The EM_SETCHARFORMAT message sets character formatting in a rich edit control.
    // SCF_SELECTION: Applies the formatting to the current selection
    RichEdit->Perform(EM_SETCHARFORMAT, SCF_SELECTION, Longint(&Format));
}
//---------------------------------------------------------------------------
// 先选中Richedit中的部分文本，然后点击此按钮，选中文本将变成上标
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    // 上标
    MySetCharFormat(RichEdit1, CFM_Superscript);
}
//---------------------------------------------------------------------------
// 先选中Richedit中的部分文本，然后点击此按钮，选中文本将变成下标
void __fastcall TForm1::Button2Click(TObject *Sender)
{
    // 下标
    MySetCharFormat(RichEdit1, CFM_Subscript);
}