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HomeJavajavaTutorialThe meaning of do in java

The do statement in Java is a loop statement, which ensures that the loop body statement block is executed at least once, and then determines whether to continue execution based on the conditional expression. It is similar to a while loop, but the first execution of the statement block is not affected by the conditional expression and is always executed once.

The meaning of do in java

The meaning of do in Java

Do in Java is a loop statement that is used to execute a statement block at least Once, and then decide whether to continue execution based on the conditional expression.

Syntax

do {
    // 语句块
} while (condition);

Working principle

  • First execution: In the loop body The statement block is executed once immediately, even if the conditional expression is false.
  • Subsequent execution: After the first execution, the condition expression will be evaluated. If true, the loop body will continue executing; if false, the loop ends.
  • Termination condition: The loop will continue to execute until the condition expression becomes false.

Differences from while loops

The do-while loop is similar to the while loop, but there are some key differences:

Features do-while loop while loop
First execution The statement block will be executed once immediately The statement block will not be executed until the condition is true
Execution order Execute the statement block first, then Check the condition Check the condition first, then execute the statement block
Execute at least once Ensure the statement block is executed at least once possible The block of statements is not executed at all

Example

The following code will print the numbers 1 to 10, even if the conditional expression is false:

int i = 0;
do {
    System.out.println(i++);
} while (i < 0);

Note: Typically, do-while loops are used to ensure that a block of statements is executed at least once, such as when processing input or initializing variables.

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