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Revision 1 of 2, by Trev on 2-17-2020. The page as it is now.

If/zh CN

If then(条件语句)

pascal
  if condition
    then statement1
    else statement2;

Condition 是布尔表达式

如果 Condition 为真则执行 statement1,否则执行 statement2。

Else 和 statement2 可省略,此时如 Condition 为假则跳过 if 语句。

注意:1. else 之前不能加分号。下面是不合法的:

pascal
  if condition
    then statement1;
    else statement2;

2.else 总是与和它最近的if配对:

pascal
  if condition1
    then if condition2 then statement1;
    else statement2;

上面的else与第二个if配对;

要使else与第一个if配对,则应写成这样:

pascal
  if condition
    then begin 
           if condition2 then statement1;
          end
    else statement2;

If语句中使用复合语句

If语句可以使用复合语句 (begin ... end Block)。

pascal
  if boolean_condition then
    begin
      statement1;
      statement2;
      statement3;
    end;

From the Free Pascal wiki, page "If/zh CN", as it stood on 2020-02-17 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.