⭐ 欢迎来到虫虫下载站! | 📦 资源下载 📁 资源专辑 ℹ️ 关于我们
⭐ 虫虫下载站

📄 constant.htm

📁 一份51的编译程序,dos版本的. 英文名字MCS-51 Microcontroller Family Macro Assembler
💻 HTM
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<!-- Constants -->

<HTML>

<HEAD>

<TITLE>Constants</TITLE>

</HEAD>

<BODY BACKGROUND="spiral.gif" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#990099" ALINK="#FF0000">

<TABLE WIDTH="98%">
<TR><TD WIDTH=60 VALIGN=BOTTOM NOWRAP>
<IMG SRC="transp.gif" ALT="" WIDTH=60 HEIGHT=20>
</TD><TD>

<!-- Ab hier Seitentext: -->

<BIG>
<BR>

<P>
<STRONG><U>III.3 Constants</U></STRONG>
</P>

<P>
Numeric constants consist of a sequence of digits, followed by a radix
specifier. The first character must always be a decimal digit.
The legal digits and radix specifiers are:
</P>

<P>
<BLOCKQUOTE>
<TABLE BORDER CELLPADDING=8>
<TR><TH>constant</TH><TH>digits </TH><TH>radix    </TH></TR>
<TR><TD>binary  </TD><TD NOWRAP>0 ... 1</TD><TD NOWRAP>B        </TD></TR>
<TR><TD>octal   </TD><TD NOWRAP>0 ... 7</TD><TD NOWRAP>Q or O   </TD></TR>
<TR><TD>decimal </TD><TD NOWRAP>0 ... 9</TD><TD NOWRAP>D or none</TD></TR>
<TR><TD>hex     </TD><TD NOWRAP>0 ... F</TD><TD NOWRAP>H        </TD></TR>
</TABLE>
</BLOCKQUOTE>
</P>

<P>
Thus, for example, the following constants are equivalent:
</P>

<P>
<BLOCKQUOTE>
<PRE>
1111111B      binary
    177Q      octal
    177o      octal
     127      decimal
    127d      decimal
    07FH      hex
</PRE>
</BLOCKQUOTE>
</P>

<P>
Character constants may be used wherever a numeric value is allowed.
A character constant consists of one or two printing characters enclosed
in single or double quotes. The quote character itself can be represented
by two subsequent quotes. For example:
</P>

<P>
<BLOCKQUOTE>
<PRE>
 'X'       8 bit constant:       58H
&quot;a@&quot;      16 bit constant:     6140H
''''       8 bit constant:       27H
</PRE>
</BLOCKQUOTE>
</P>

<P>
In DB statements, character constants may have any length.
In this case, we call it a character string. For example:
</P>

<P>
<BLOCKQUOTE>
<PRE>
'This is only text!'
</PRE>
</BLOCKQUOTE>
</P>

</BIG>

<!-- Seitentext Ende -->

<P>
<BR>
<BR>
<CENTER>
<TABLE WIDTH="70%">
<TR><TH><A HREF="contents.htm"><IMG SRC="home.gif" ALT="[contents]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH>
    <TH><A HREF="language.htm"><IMG SRC="up.gif" ALT="[up]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH>
    <TH><A HREF="symbols.htm"><IMG SRC="back.gif" ALT="[back]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH>
    <TH><A HREF="express.htm"><IMG SRC="next.gif" ALT="[next]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH>
</TR>
</TABLE>
</CENTER>
</P>

</TD></TR>
</TABLE>

</BODY>

</HTML>

⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -