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This article shows you what the four looping methods in java are, which are concise and easy to understand, which will definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

Java cycle structure

Program statements with sequential structures can only be executed once. If you want to perform the same operation multiple times, you need to use a loop structure.

There are three main loop structures in java: while loops do...while loops for loops introduce an enhanced for loop that is mainly used in arrays in java5. 1.while cycle

While is the most basic loop, which has the following structure:

Package com.example.lesson1;//while (true/false expression) {/ / Loop content / / as long as the Boolean expression is the body of the true loop, it will always be executed. / / Let's take a look at an example: public class Test {public static void main (String args []) {int x = 10; while (x < 20) {System.out.print ("value of x:" + x); x examples; System.out.print ("\ n") }}}

The compilation and running structure of the above example is as follows:

Value of x: 10value of x: 11...value of x: 192.do... While cycle

For while statements, you cannot enter a loop if the condition is not met. But sometimes we need to execute at least once, even if the conditions are not met.

Do... The while loop is the same as the while loop, except that

Do... The while loop is executed at least once.

Package com.example.lesson1;//do {/ Code statement / /} while (Boolean expression); / / Note: the Boolean expression is after the body of the loop, so the statement block is executed before the Boolean expression is detected. If the Boolean expression value is true, the statement block / / executes until the value of the Boolean expression is false. / / example: public class Test {public static void main (Staing args []) {int x = 10; do {System.out.print ("value of x:" + x); System.out.print ("\ n") } while (x < 20);}}

The compilation and running results of the above examples are as follows:

Value of x: 10...value of x: 193.for loop

Although all loop structures can be used with while or do... While said, but java provides another kind of statement (for loop), which makes some loop structures simpler.

The number of times the for loop is executed is determined before execution. The syntax format is as follows: / / for (1 initialization; 2 Boolean expression; 4 update) {3 for / code statement / /} / there are the following notes about the for loop: / / 1, execute the initialization step first. You can declare a type, but you can initialize one or more loop control variables, or it can be an empty statement. / / 2, then, detect the value of the Boolean expression. In the case of true, the loop body is executed, and in the case of false, the loop body terminates and starts executing the statements that follow the loop. / / 3, after executing a loop, update the loop control variable. / / 4, detect the Boolean expression again. Loop through the above process. Public class Test {public static void main (Staing args []) {for (int Xerox)

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