test

<pre name="code" class="cpp">#include <iostream>#include <Cmath>using namespace std;int main(){    double x,y;    int c;    cout <<"请输入大于0 的实数值x"<<endl;    cin >> x;    if(x < 0)        cout<<"Input error!"<<endl;    else    {        c = int (x)/2;        switch(c)        {        case 0:            y = x;break;        case 1:        case 2:            y = x * x + 1;break;        case 3:        case 4:            y = sqrt(x + 1);break;        default:            y = 1/(x + 1);break;        }            cout <<"y = "<< y <<endl;    }}