傅里叶变换

#include<iostream>

#include<bitset>

#include<vector>

#include<cstdlib>

#include<complex>

#include<cmath>



const double PI = atan(1.0)*4.0;

int n = 0;

using namespace std;



int power(int pow)

{

    int result = 1;

    for(int i = 0;i != pow;i++)

    result *= 2;

    return result;

}



unsigned long rey(unsigned int k,int pow)

{

    bitset<32> bit(k);

    bitset<32> bitnew(0);

    int i = pow,j = 0;

    for(;i>=0;i--)

        bitnew[j++] = bit[i];

    cout<<bitnew<<endl;

    unsigned long newk = bitnew.to_ulong();

    return newk;

}