递归2： 十进制转换成二进制的递归与迭代实现

#include <iostream>using namespace std;// 前置条件： n >= 0// 后置条件： 输出n的二进制等值数// (递归版本--优于迭代版本)// worstTime(n) 是 O(log n).void writebinary1(int n){if (n == 0 || n == 1)cout << n;else{writebinary1(n/2);cout << n%2;}}// (迭代版本)// 描述：用一个while循环生成位的值，并用一个数组保存这些值，//然后是一个反序步骤的for循环输出那些值。// worstTime(n) 是 O(n).void writebinary2(int n){int i = 0, bin[32];if (n == 0 || n == 1){bin[0] = n;i++;}while (n != 1 && n != 0){bin[i] = n % 2;i++;n = n / 2;}bin[i] = n;for (int j = i; j >= 0; j--)cout << bin[j];}int main(){cout << "Please enter a integer:\n";int n;cin >> n;cout << "(decimal) " << n << " = (binary) ";writebinary1(n);cout << endl << endl;cout << "Now, please enter a integer:\n";cin >> n;cout << "(decimal) " << n << " = (binary) ";writebinary2(n);cout << endl;return 0;}