What is the meaning and usage of do in java

do is the keyword to create a do-while loop in Java. Its characteristics are: the loop condition is checked after the loop body is executed; no matter whether the condition is true or not, the loop body will be executed at least once; different from the while loop , the execution order is to execute the loop body first and then check the conditions.

What is do in Java?

do is a keyword in Java that is used to create do-while loops. A do-while loop is similar to a while loop, but its loop condition is checked after the loop body is executed.

Usage

<code class="java">do {
    // 循环体
} while (循环条件);</code>

• Loop body: Contains statements to be executed repeatedly.
• Loop condition: Boolean condition checked after the loop body is executed. If the condition is true, the loop continues; if it is false, the loop terminates.

Difference from while loop

The main difference between do-while loop and while loop is:

• Execution Sequence: In a do-while loop, the loop body is always executed once first, and then the loop condition is checked; in a while loop, the loop condition is checked first, and then the loop body is executed.
• Execute at least once: The do-while loop executes the loop body at least once, even if the loop condition is false when executed for the first time; while the while loop may not execute the loop body if the loop The condition is initially false.

Example

<code class="java">int i = 0;
do {
    System.out.println(i);
    i++;
} while (i < 5);</code>

In this example, the loop body is executed once (output i is 0), and then the loop condition is checked (i < 5) . The loop condition is true, so the loop continues executing with outputs i being 1, 2, 3, and 4. When i equals 5, the loop condition becomes false and the loop terminates.

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