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Help me add arrays to this code.

spring2014 (60)
Hi. This code reads data from file 3 times and do the calculations and write the results in other file. Would you please help me write the for loop with array? I mean what if I just want the second and third output?
something like this :

for (i=0; i<3; i++)
{
inputFile1>>tf[i];
inputFile2>>xi[i];
inputFile3>>vi[i];
inputFile4>>dt[i];
inputFile5>>tmax[i];



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  #include <iostream>
#include <cmath>
#include <fstream>


using namespace std;

/* function prototypes */

double f1(double, double, double);
double f2(double, double, double);

double euler2m(double(*)(double, double, double),
               double(*)(double, double, double),
               double, double, double, double,
               double&, double&);

int main()
{
    double ti, xi, vi, tf, xf, vf, dt, tmax;
    int i;


/* initial information */


    /*cout<<"enter the initial value for variable as (ti)"<<endl;
    cin>>ti;
    cout<<"initial value for function x(t) as xi"<<endl;
    cin>>xi;
    cout<<"enter the initial (vi)"<<endl;
    cin>>vi;
    cout<<"enter the step size for integration as dt"<<endl;
    cin>>dt;
    cout<<"enter the tmax to integrate from ti till tmax"<<endl;
    cin>>tmax; */
    ifstream inputFile1("afile-ti.txt");
    ifstream inputFile2("afile-xi.txt");
    ifstream inputFile3("afile-vi.txt");
    ifstream inputFile4("afile-dt.txt");
    ifstream inputFile5("afile-tmax.txt");
    ofstream outputFile("output3.txt");
 /*
    ti = 0.0;             // initial value for variable
    xi = 0.0;             // initial value for function x(t)
    vi = 1.0;             // initial
    dt = 0.1;             // step size for integration
    tmax = 12.0;          // integrate from ti till tmax */

           for (i=0; i<3; i++)
           {
            inputFile1>>tf;
        	inputFile2>>xi;
        	inputFile3>>vi;
        	inputFile4>>dt;
        	inputFile5>>tmax;




/* integration of ODE */
    while (ti <= tmax)
    {
    	tf = ti + dt;
    	euler2m(f1,f2,ti,xi,vi,tf,xf,vf);

        ti = tf;
        xi = xf;
        vi = vf;
    }
    cout<<"t="<<tf<<"\t"<<"x="<<xf<<"\t"<<"x'="<<vf<<"\n";
    outputFile<<"t="<<tf<<"\t"<<"x="<<xf<<"\t"<<"x'="<<vf<<"\n";
           }
    return 0;
}

/*
  Definition of the x'(t) = f1(t,x,x') = x' by the definition
*/
    double f1(double t, double x, double v)
{
    double d1x;
    d1x = v;
    return d1x;
}
/*
 *  Definition of the x"(t) = f2(t,x,x')
*/
    double f2(double t, double x, double v)
{
    double d2x;
    d2x = (t*t);
    return d2x;
}

//-----------------------------------------------------------------------

    double euler2m(double(*d1x)(double, double, double),
                   double(*d2x)(double, double, double),
                   double ti, double xi, double vi, double tf,
                   double& xf, double& vf)
    {
        xf = xi + d1x(ti,xi,vi)*(tf-ti);
        vf = vi + d2x(ti,xi,vi)*(tf-ti);
    /* correction */
        xf = xi + (d1x(ti,xi,vi)+d1x(ti,xf,vf))*0.5*(tf-ti);
        vf = vi + (d2x(ti,xi,vi)+d2x(ti,xf,vf))*0.5*(tf-ti);
       return 0.0;
    }
TheKingOfTyrants (232)
Line 20. You'd have to make all of declare your variables as arrays.
double ti[3], xi[3], vi[3], tf[3], xf[3], vf[3], dt[3], tmax;
spring2014 (60)
are you sure?
What about between lines 97 and 110?
TheKingOfTyrants (232)
You'd have to iterate through the array and call the euler2m function each iteration. So something like this:
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for (int i = 0; i < 3; i++)
{
    euler2m( f1, f2, ti[i], xi[i], vi[i], tf[i], xf[i], vf[i]);
}
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