Java while Loop: Repeating Execution While Conditions Are Met, with Examples
The Java `while` loop is used to repeatedly execute code, with the core idea being "execute the loop body as long as the condition is met, until the condition is no longer satisfied." The syntax is `while(conditionExpression) { loopBody }`, where the condition must be a boolean value, and the loop body is recommended to be enclosed in braces. Manually writing repeated code (e.g., printing numbers 1-5) is cumbersome when no loop is needed, whereas the `while` loop simplifies this. For example, to print 1-5: initialize `i=1`, then `while(i<=5)` executes the print statement and increments `i` (to avoid an infinite loop). When calculating the sum of numbers 1-10, initialize `sum=0` and `i=1`, then `while(i<=10)` adds `i` to `sum`, and the total sum (55) is printed. Infinite loops should be avoided: ensure the condition is never `true` permanently or that the condition variable is not modified (e.g., forgetting `i++`). Always include logic in the loop body that will make the condition `false`. The `do-while` loop is also introduced, which executes the loop body first and then checks the condition, guaranteeing execution at least once. In summary, the `while` loop is suitable for repeated scenarios where the condition is met (e.g., printing sequences, summing values). Be cautious of infinite loops, and proficiency will come with practice.
Read MoreMastering C++ while Loops: Differences from for Loops and Applications
This article introduces the usage of while loops in C++, their differences from for loops, and their application scenarios. Loops are used to repeatedly execute code, avoiding manual repetitive input. In C++, a while loop first checks the condition; if true, the loop body is executed, and then the condition is updated until the condition becomes false. For example, printing numbers from 1 to 10 or calculating a sum requires that there must be an operation to update the condition (such as i++) in the loop body, otherwise, an infinite loop will occur. While loops and for loops are suitable for different scenarios: while loops are suitable for situations where the condition is continuously changing and the number of iterations is uncertain (e.g., user input validation until correct input is entered); for loops are suitable for known loop counts (e.g., traversing an array) and have a more compact syntax. In practical applications, while loops are used to handle tasks with an uncertain number of iterations (e.g., reading input until -1 is entered) or scenarios requiring continuous condition checks (e.g., a number guessing game). It is important to avoid infinite loops and ensure that the condition will eventually become "false". Mastery can be achieved quickly through practicing basic examples, such as printing numbers or calculating sums.
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