Why can't initialize an arrary member in the structre

Why I cant use s.sales[4]={0.0,0.0,0.0,0.0},to in initialize the array memeber in the Sales structure , the posted code is successful. It's wired.

  namespace SALES
{

    void setSales(Sales & s)
    {

        s.sales[0] = { 0.0 };
        s.sales[1] = { 0.0 };
        s.sales[2] = { 0.0 };
        s.sales[3] = { 0.0 };
        s.max = 0.0;
        s.average = 0.0;
        s.min = 0.0;
    }.....
}