可使用c++自带函数net_permutation()

#include<iostream>
#include<algorithm>
using namespace std;

int main()
{
    int a[3]={1,2,3};
    do
    {
        cout<<a[0]<<" "<<a[1]<<" "<<a[2]<<endl;
    }while(next_permutation(a,a+3));
}