【vector容器】求解完数的判断

解题思路:

void cheaknum(int n)//利用vector储存所有N以内每个数的因子，检查满足条件就打印

注意事项:

现在研究出来的完数均是偶数，所以先判断是否是偶数偷懒可以有效减少运算时间
参考代码:

#include<iostream>

#include<vector>

using namespace std;

void cheaknum(int n)

{ vector<int> factor(1);

int sum = 0;

factor[0] = 1;

for (int f1 = 2; f1 <= (n / 2); f1++) {

if ((n % f1) == 0) {

factor.push_back(f1);

}

}

for (vector<int>::iterator it = factor.begin(); it != factor.end(); it++)

{

sum = sum + (*it);

}

if(sum==n) {

cout << n << " " << "its factors are" << " ";

for (vector<int>::iterator it = factor.begin(); it != factor.end(); it++)

{

cout << *it << " ";

}

cout << endl;

}

}

int main(){

int n;

cin >> n;

for (int a = 2; a <= n; a++) {

if (a % 2 == 0) {

cheaknum(a);

}

}

}