Largest number problem

#1

#include
using namespace std;

int main() {

double n1, n2, n3;

cout << "Enter three numbers: ";
cin >> n1 >> n2 >> n3;

// check if n1 is the largest number
if(n1 >= n2 && n1 >= n3)
    cout << "Largest number: " << n1;

// check if n2 is the largest number
else if(n2 >= n1 && n2 >= n3)
    cout << "Largest number: " << n2;

// if neither n1 nor n2 are the largest, n3 is the largest
else 
    cout << "Largest number: " << n3;

return 0;

}

Why it is wrong