Perl for cycle

Grammar

The syntax format is as follows:

for ( init; condition; increment ){
   statement(s);
}

The following is for analysis of the control flow of the loop:

1. init will be executed first, and only once. This step allows you to declare and initialize any loop control variables. You can also not write any statements here, as long as a semicolon appears.

2. Next, it will judge condition . If for true loop body is executed if for false The loop body is not executed, and the control flow jumps to the following for next statement of the loop.

3. After the execution for after looping the body, the control flow jumps back to the increment statement. This statement allows you to update loop control variables. This statement can be left blank as long as a semicolon appears after the condition.

4. The conditions are judged again. If for true loop is executed, and the process is repeated over and over again (loop body, then increase the step value, and then rejudge the condition) when the condition becomes false, for cycle ends.

Here, statement(s) can be a single statement or a block of code madeup of several statements.

condition can be any expression when the condition is true the loopis executed when the condition is false , exit the loop.

Flow chart

#!/usr/bin/perl# execute for
circulatefor($a=0;$a<10;$a=$a+1){print"a's value is:$a\\n";}

The value of a is: 0
The value of a is: 1
The value of a is: 2
The value of a is: 3
The value of a is: 4
The value of a is: 5
The value of a is: 6
The value of a is: 7
The value of a is: 8
The value of a is: 9