suma maxima a4 nr reale

#include <iostream>

using namespace std;

int main()
{
    float a, b, c,d, s=0;
    cout<<"a=";cin>>a;
    cout<<"b=";cin>>b;
    cout<<"c=";cin>>c;
    cout<<"d=";cin>>d;
    if(a>0)
        s=s+a;
    else
        s=s;
    if(b>0)
        s=s+b;
    else
        s=s;
    if(c>0)
        s=s+c;
    else
        s=s;
    if(d>0)
        s=s+d;
    else
        s=s;
    cout<<"s="<<s;


    return 0;