n个数从小到大排序（n

//n(n<20)个数按从大到小排序
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int cmp(int a,int b)
{
int n1,n2;
if(a > b)
    {
        n1 = b;
        n2 = a;
    }
else
    {
        n1 = a;
        n2 = b;
    }
return n1 < n2;
}
int main()
{   
int n,arr[20],i=0;
cout<<"输入要参与排序的数的个数n(n<20):"<<endl;
cin>>n;
cout<<"输入"<<n<<"个数："<<endl;
for(;i < n;i++)
cin>>arr[i];
    sort(&arr[1],&arr[n-1],cmp);
for(i = 0;i<n;i++)
cout<<arr[i]<<endl;
}
//编译没问题，运行会有错误提示：invalid operation<，忽略两次就可以了。。。偶也不造为嘛/(ㄒoㄒ)/~~