1、:=是賦值號，不能比較大小
2、A=s是不對的，字符要用單引號表示
3、a、b變量未定義
case of 用法
case anchar of
'a':Dosth1;
'b':Dosth2;
else DoElseSth;
end;
program ex01;
var
a,b:char;//char是字符型
//這裏s表示拳頭，a表示剪刀，b表示布；輸入時要像sa這樣連在壹起輸入
begin
write('Which one would you choose(s,a,b):');
readln(a,b);
if ((a='s') and (b='a')) or ((a='a') and (b='b')) or ((a='b') and (b='s')) then writeln('A wins!') else
if a=b then writeln('no one wins')
else writeln('b wins');
end.