77 lines
1.5 KiB
C++
77 lines
1.5 KiB
C++
/**
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* File: iteration.cpp
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* Created Time: 2023-08-24
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* Author: krahets (krahets@163.com)
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*/
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#include "../utils/common.hpp"
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/* for 循环 */
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int forLoop(int n) {
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int res = 0;
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// 循环求和 1, 2, ..., n-1, n
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for (int 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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int whileLoop(int n) {
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int res = 0;
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int 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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int whileLoopII(int n) {
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int res = 0;
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int 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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string nestedForLoop(int n) {
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ostringstream res;
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// 循环 i = 1, 2, ..., n-1, n
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for (int i = 1; i <= n; ++i) {
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// 循环 j = 1, 2, ..., n-1, n
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for (int 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.str();
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}
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/* Driver Code */
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int main() {
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int n = 5;
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int res;
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res = forLoop(n);
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cout << "\nfor 循环的求和结果 res = " << res << endl;
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res = whileLoop(n);
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cout << "\nwhile 循环的求和结果 res = " << res << endl;
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res = whileLoopII(n);
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cout << "\nwhile 循环（两次更新）求和结果 res = " << res << endl;
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string resStr = nestedForLoop(n);
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cout << "\n双层 for 循环的遍历结果 " << resStr << endl;
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return 0;
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}
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