41 lines
1.7 KiB
Markdown
41 lines
1.7 KiB
Markdown
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---
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title: While Loop
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---
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# While Loop
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The `while` loop repeatedly executes the block of statements until the condition specified within the parentheses evaluates to `false`. For instance:
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```java
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while (some_condition_is_true)
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{
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// do something
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}
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```
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Each 'iteration' (of executing the block of statements) is preceeded by the evaluation of the condition specified within the parentheses - The statements are executed only if the condition evaluates to `true`. If it evaluates to `false`, the execution of the program resumes from the the statement just after the `while` block.
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**Note**: For the `while` loop to start executing, you'd require the condition to be `true` initially. However, to exit the loop, you must do something within the block of statements to eventually reach an iteration when the condition evaluates to `false` (as done below). Otherwise the loop will execute forever. (In practice, it will run until the <a href='https://guide.freecodecamp.org/java/the-java-virtual-machine-jvm' target='_blank' rel='nofollow'>JVM</a> runs out of memory.)
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## Example
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In the following example, the `expression` is given by `iter_While < 10`. We increment `iter_While` by `1` each time the loop is executed. The `while`loop breaks when`iter_While`value reaches `10`.
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```java
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int iter_While = 0;
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while (iter_While < 10)
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{
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System.out.print(iter_While + " ");
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// Increment the counter
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// Iterated 10 times, iter_While 0,1,2...9
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iter_While++;
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}
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System.out.println("iter_While Value: " + iter_While);
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```
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Output:
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```
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0 1 2 3 4 5 6 7 8 9
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iter_While Value: 10
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```
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 [Run Code](https://repl.it/CJYj/0)
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