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For loops

Format:

[sourcecode language=”java” toolbar=”false”]
for (initialization; termination; increment) {
statement(s)
}
[/sourcecode]

  • initialization : initializes the loop; executes once at the beginning.
  • when termination expression evaluates to false, the loop terminates.
  • increment : is invoked after each iteration through the loop.

The order of execution:

  • the variable is initialized then
  • it is checked to see if the expression is true,
  • if true the statements are executed,
  • then the variable is incremented,
  • then expression is tested,
  • if true the statements are executed…

[initialized, tested, executed, incremented, tested, executed, incremented…]

[sourcecode language=”java” toolbar=”false”]
for(int x=0; x<5; x++)
for(int x=0; x<5; ++x)
[/sourcecode]

0 to 4, using a post- or pre-increment does not affect the number of loops.

[sourcecode language=”java” toolbar=”false”]
for(int x=0; x<=5; x++)
[/sourcecode]

0 to 5, using = includes the number.

[sourcecode language=”java” toolbar=”false”]
for(int x=5; x>0; x–)
[/sourcecode]

5 to 1, using < or > excludes the number.

Invalid

[sourcecode language=”java” toolbar=”false”]
for(int x = 0, int z = 0 ; x < 10; x++){}
[/sourcecode]

Cannot declare a second variable inside a for loop initialisation.

Correct

[sourcecode language=”java” toolbar=”false”]
for(int x = 0, z = 0 ; x < 10; x++){}
[/sourcecode]

But you can initialise another variable.

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