c++6.0程序设计基础

Question

计算算式：1+2¹+2²+2³+...2的n次方。要求n由键盘输入

Answer 1

写程序并不是实现功能就完了，还要看代码的美观和精悍，也许这就是高手们写的艺术吧

Answer 2

#include <iostream>#include <cmath>using namespace std;int main() {     cout << "Enter n:";     int n;     cin >> n;     cout <<( pow(2,n+1) -1)<<endl;     return 0;}这是求等比数列之和，用等比数列之和公式才是建议的，并不是呆板的搞个for循环去求和

Answer 3

#include <iostream>#include <cmath>using namespace std;int main() {     cout << "Enter n:";     int n;     cin >> n;     int sum = 0;     for(int i = 0; i <= n; i++)          sum += pow(2,i);     cout << sum;     return 0;}

Answer 4

#include <stdio.h> void main() { int i,n,m,sum; scanf("%d",&n); for(m=1,sum=0,i=1;i<=n;n++) { m=2*m; sum=m+sum; } }