Write sort second-level sorting in C ++ class

When I was doing TC, I got stuck in this issue. Later I asked Daniel, you can write it like this.

1 class evenroute {
2 public:
3 struct node {
4 int X;
5 Int y;
6 node (int A = 0, int B = 0): X (A), y (B ){}
7 };
8
9 static bool CMP (const node & C, const node & D) {// Add static
10 if (C. x = D. X) return C. Y <D. Y;
11 return C. x <D. X;
12}
13
14 string isitpossible (vector <int> X, vector <int> Y, int W ){
15 struct node A [1000];
16 int n = 1000;
17 //....
18 sort (A, A + N, CMP );
19 Return "can ";
20}
21 };