Untitled

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;

//Q3
double cubic(double a[4], double x, double &f);

int main() {
    // Write C++ code here
    int i;
   double a[4] = {1,3,2,4};
   double x,f, ans;
   
   cout << "\ninput a(0-3):";
   cin >> a[i];
   cout << "\ninput x:";
   cin >> x;
   
   ans = cubic(a,x,f);
   cout << ans;
    

    
}

double cubic(double a[4], double x, double &f){
    int i;
    for(i=0; i<=3; i++){
        
        f = a[i]*pow(x,i);
        
        
    }
    
    return  f = a[i]*pow(x,i);
}