以2的幂递增循环

Question

我知道这是一件非常简单的事情，但我无法弄清楚如何以2的幂增加循环。该程序正在比较插入排序和合并排序，n应该增加功率，即2,4,8,16,32 ....这就是我所拥有的

#include <iostream>
#include <math.h>
using namespace std;


int main()
{
    int a,n,b;
    double mergesort;
    double insertionsort;

    cout << "Enter a and b values ";
    cin >> a >> b;

    do
    {
        for(n=2; n=pow(n,++);
        {
        insertionsort = a*pow(n,2);
        mergesort = b*n*log2(n);
        }

        cout <<"insertion sort= " << insertionsort << "merge sort= " <<mergesort;
        cout <<"n" << n;

    }while(insertionsort < mergesort);

    cout << "Value of n that insertion beat merge sort is " << " n ";
}

Answer 1

此循环每次迭代的次数增加n，最多为n_max：

for (int n = 2; n <= n_max; n *= 2) {
    //...
}