Check for Non-Degenerate Triangle using C++

#include <bits/stdc++.h>
using namespace std;

void CheckTriangle(vector<int> a) {
    int len = a.size();
    bool checker = false;
    sort(a.begin(), a.end()); // sequence must be in non-decreasing order
    for(int i = 0; i + 2 < len; i++) {
        if(a[i] + a[i+1] > a[i+2]) {
            checker = true;
            break;
        }
    }
    cout << "Triangle " << (checker ? "can" : "cannot") << " be formed.\n";
}

int main() {
    int n;
    cin >> n;
    if(n < 3) {
        cout << "Not enough sides.\n";
    } else {
        vector<int> a(n);
        for(int i = 0; i < n; i++) {
            cin >> a[i];
        }
        CheckTriangle(a);
    }
    return 0;
}