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for (<initialization>; <condition>; <change>) {
<block>
}
==================================================
public class Example {
public static void main(String[] args) {
for (int i=1; i<=10; i++) {
System.out.println(i);
}
}
}
Output:
1
2
3
4
5
6
7
8
9
10
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Components of the loop are all optional - so you can omit the initialization, condition clause or modification (or even all of them).
However, semicolons are mandatory.
public static void main(String[] args) {
// variable initialized outside for-loop
int i = 1;
for (; i<=10; i++) {
System.out.println(i);
}
// making the variable modification inside the loop
for (int j = 5; j > 1;) {
System.out.println(j);
j--;
}
// eternal loop
for(;;) {
// this is printed until the user
// closes the program: in practice the same as while(true)
System.out.println("Hi!");
}
}
}
==================================================
A change in the value of a variable in a for statement is usually done with the ++ and -- operators.
These operators increase or decrease the value of a variable by one, for example:
public class Example {
public static void main(String[] args) {
int a = 3;
a++;
System.out.println(a);
a--;
a--;
System.out.println(a);
// This first prints the value and then
// after that increases it:
System.out.println(a++);
// one more print
System.out.println(a);
}
}
Output:
4
2
2
3
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