C++ Array element update via transform() function

#include <iostream>
#include <algorithm>
using namespace std;
int main()/*from  ww w . j a va 2s  .  c  om*/
{                          // array of inches values
    double inches[] = { 3.5, 6.2, 1.0, 12.75, 4.33 };
    double centi[5];
    double in_to_cm(double);   // prototype
    // transform into array centi[]
    transform(inches, inches+5, centi, in_to_cm);
    for(int j=0; j<5; j++)     // display array centi[]
       cout << centi[j] << ' ';
    cout << endl;
    return 0;
}
double in_to_cm(double in)    // convert inches to centimeters
{
    return (in * 2.54);        // return result
}