77 lines
1.4 KiB
PHP
77 lines
1.4 KiB
PHP
<?php
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/**
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* File: iteration.php
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* Created Time: 2024-05-19
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* Author: DoWake (admin@mengxing.cc)
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*/
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/* for 循环 */
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function forLoop($n)
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{
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$res = 0;
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// 循环求和 1, 2, ..., n-1, n
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for ($i = 1; $i <= $n; $i++) {
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$res += $i;
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}
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return $res;
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}
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/* while 循环 */
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function whileLoop($n)
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{
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$res = 0;
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$i = 1; // 初始化条件变量
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// 循环求和 1, 2, ..., n-1, n
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while ($i <= $n) {
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$res += $i;
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$i++; // 更新条件变量
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}
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return $res;
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}
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/* while 循环（两次更新） */
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function whileLoopII($n)
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{
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$res = 0;
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$i = 1; // 初始化条件变量
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// 循环求和 1, 4, 10, ...
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while ($i <= $n) {
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$res += $i;
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// 更新条件变量
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$i++;
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$i *= 2;
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}
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return $res;
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}
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/* 双层 for 循环 */
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function nestedForLoop($n)
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{
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$res = '';
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// 循环 i = 1, 2, ..., n-1, n
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for ($i = 1; $i <= $n; $i++) {
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// 循环 j = 1, 2, ..., n-1, n
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for ($j = 1; $j <= $n; $j++) {
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$res .= '(' . $i . ', ' . $j . '), ';
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}
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}
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return $res;
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}
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/* Driver Code */
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$n = 5;
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$res = 0;
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$res = forLoop($n);
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echo "\nfor 循环的求和结果 res = {$res}" . PHP_EOL;
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$res = whileLoop($n);
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echo "\nwhile 循环的求和结果 res = {$res}" . PHP_EOL;
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$res = whileLoopII($n);
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echo "\nwhile 循环（两次更新）求和结果 res = {$res}" . PHP_EOL;
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$resStr = nestedForLoop($n);
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echo "\n双层 for 循环的遍历结果 {$resStr}" . PHP_EOL;
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