Mega Code Archive
0052 while loop
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The while loop repeats a statement or block while its controlling expression is true. Here is its general form:
while(condition) {
// body of loop
}
The condition can be any Boolean expression.
The body of the loop will be executed as long as the conditional expression is true.
The curly braces are unnecessary if only a single statement is being repeated.
Here is a while loop that counts down from 10, printing exactly ten lines of "tick":
public class Main {
public static void main(String args[]) {
int n = 10;
while (n > 0) {
System.out.println("n:" + n);
n--;
}
}
}
When you run this program, you will get the following result:
n:10
n:9
n:8
n:7
n:6
n:5
n:4
n:3
n:2
n:1
The body of the while loop will not execute if the condition is false. For example, in the following fragment, the call to println() is never executed:
public class Main {
public static void main(String[] argv) {
int a = 10, b = 20;
while (a > b) {
System.out.println("This will not be displayed");
}
System.out.println("You are here");
}
}
The output:
You are here
The body of the while can be empty. For example, consider the following program:
public class Main {
public static void main(String args[]) {
int i, j;
i = 10;
j = 20;
// find midpoint between i and j
while (++i < --j)
;
System.out.println("Midpoint is " + i);
}
}
It generates the following output:
Midpoint is 15
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