Sas 错误表示没有给出变量X，但变量X在前面声明过

在SAS中尝试绘制时，我遇到一个错误，错误是没有给出变量X，但变量X在前面声明过

这是我的密码：

data prg7_5;
do a=1 to 3;
input x@@;
output
end;
cards;
7028 1764 600 7228 2036 744 
7228 2130 804 8448 2536 844
8567 2436 912 9061 2436 1128 
9167 3108 1320 9167 3108 1464 
10032 3108 1608 10051 3208 1896
;
run;
goptions hsize=5 vsize=4 ftext='宋体';
footnote 'the time ';
symbol1 interpol=boxt00 width=1.8 bwidth=5 co=red;
axis1 label  =('temperature(C)')
    value=('190' ' 220 ' '260')
    minor=none
    offset=(10,10);
axis2 label =(angle=90'the time')
    offset=(0,0);
proc gplot data= prg7_5;
    plot x*a/haxis=axis1
        vaxis=axis2;
run;

以下是运行日志：

---

你能告诉我做这件事的正确方法吗？请帮助

输出后需要分号。您的数据集将为空，并且出现以下错误

  ERROR 117-185: There was 1 unclosed DO block.

 NOTE: The SAS System stopped processing this step because of errors.
WARNING: The data set WORK.PRG7_5 may be incomplete.  When this step was stopped 
there were 0 observations and 2 variables.
WARNING: Data set WORK.PRG7_5 was not replaced because this step was stopped.

在输出处用分号更改代码，如下所示

 do a=1 to 3;
  input x@@;
  output;
 end;

---

调试时，请修复第一个错误，因为后面的错误可能是早期故障的副作用，如本例所示。