Perl Learning Four: Statements (cont.)

Loop control:
1.last
Statement block for Exit label
2.next

3.redo
Not recommended, cycle times are not controllable

4.goto
Not recommended.
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Label:

Define a label first
Last|next|redo|goto label;

Last VS next corresponds to the C language:
Last ==>break
Next ==>continue
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Perl's continue statement:
continue{statement} is not the same as in C
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Single-line conditional statement and Loop statement
statement + condition;

Unless:print $a unless ($a ==0);
While:print $a while ($a-==0);
Untile:print $a untile ($a-=0);
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With && | | The conditional statement (* * *)
$a ==0&&print &a;
Open (F, ' file ') | | Die "can ' t open";

****************************************
Die
Warn

$!: Internal variable, containing error code

[Email protected]: internal variable, containing error message

Perl Learning Four: Statements (cont.)