So in my program I have to use specific values obtained from an inputfile in different functions, and I couldn't figure out a good way to do this. I don't want to have to have the user input the file name for every function. I tried it this way, but it doesn't work. Could this possibly work, or is there a better way?

```
#include <iostream>
#include <cmath>
#include <fstream>
using namespace std;
double deflectioni (double, double, double, double, double, double, char);
double deflectionc (double, double, char);
double slopei (double, double, double, double, double, double, char);
double slopec (double, double, char);
int main()
{
cout<<"Program to calculate deflection and rotation at incremental points" <<endl;
cout<<"along the length of a beam" <<endl;
cout<<"Kelli Harding - September 29, 2012" <<endl;
cout<<endl;
char inputfilename[50];
char outputfilename[50];
double span, load, modulus, deltax, b1, b2, b3, d1, d2, d3;
double def, x, slope, dinner, douter;
string type;
ofstream outputfile;
ifstream inputfile;
cout <<"Enter the name of the file you wish to open." <<endl;
cin >> inputfilename;
inputfile.open(inputfilename);
if (!inputfile.eof())
{
inputfile >>deltax;
inputfile >>type;
}
cout <<"Enter the name of the file you wish to write to." <<endl;
cin >> outputfilename;
outputfile.open(outputfilename);
if (!outputfile)
{
cout <<"Error opending output file: " <<outputfilename <<endl;
cout <<"Check if file already exists." <<endl;
return 0;
}
cout <<"Output file successfully opened." <<endl;
outputfile <<"Distance x (m) \t";
outputfile <<"Deflection (m) \t";
outputfile <<"Rotation" <<endl;
if (type=="I-section")
{
inputfile >>b1;
inputfile >>b2;
inputfile >>b3;
inputfile >>d1;
inputfile >>d2;
inputfile >>d3;
inputfile >>type;
int i=1;
do
{
x=deltax*i++;
outputfile<<x;
outputfile<<"\t \t";
def=deflectioni (b1, b2, b3, d1, d2, d3, inputfilename);
outputfile<<def;
outputfile<<"\t";
slope=slopei (b1, b2, b3, d1, d2, d3,inputfilename);
outputfile<<slope <<endl;
} while (x<=span-deltax);
}
else if (type=="Circular")
{
inputfile >>dinner;
inputfile >>douter;
int i=1;
do
{
x=deltax*i++;
outputfile<<x;
outputfile<<"\t \t";
def=deflectionc(dinner, douter, inputfilename);
outputfile<<def;
outputfile<<"\t";
slope=slopec(dinner, douter, inputfilename);
outputfile<<slope <<endl;
} while (x<=span-deltax);
}
inputfile.close();
outputfile.close();
system ("PAUSE");
return 0;
}
double deflectioni (double b1, double b2, double b3, double d1, double d2, double d3, char inputfilename) {
double c1, c2, moi, I1, I2, I3, def;
c2=((b1*d1)*(d1/2)+(b2*d2*(d1+(d2/2)))+(b3*d3*(d1+d2+(d3/2))))/((b1*d1)+(b2*d2)+(b3*d3));
c1=(d1+d2+d3)-c2;
I1=(pow(d1,3)*b1)/12+(pow(c2-(d1/2),2)*b1*d1);
I2=(pow(d2,3)*b2)/12+(pow((d1+(d2/2)-c2),2)*b2*d2);
I3=(pow(d3,3)*b3)/12+(pow((d1+d2+(d3/2)-c2),2)*b3*d3);
moi=I1+I2+I3;
double span, load, modulus, deltax;
double x, slope;
ifstream inputfile;
inputfile.open(inputfilename);
if (!inputfile.eof())
{
inputfile >>span;
inputfile >>load;
inputfile >>modulus;
}
def=((load*pow(x,2))/(24*modulus*moi))*(6*pow(span,2)-(4*span*x)+pow(x,2));
return (def); }
double deflectionc (double dinner, double douter, char inputfilename) {
double moi, def, x;
moi=(3.1416/64)*(pow(douter,4)-(pow(dinner,4)));
double span, load, modulus, deltax;
ifstream inputfile;
inputfile.open(inputfilename);
if (!inputfile.eof())
{
inputfile >>span;
inputfile >>load;
inputfile >>modulus;
}
def=((load*pow(x,2))/(24*modulus*moi))*(6*pow(span,2)-(4*span*x)+pow(x,2));
return (def); }
double slopei (double b1, double b2, double b3, double d1, double d2, double d3, char inputfilename) {
double c1, c2, moi, I1, I2, I3, slope;
c2=((b1*d1)*(d1/2)+(b2*d2*(d1+(d2/2)))+(b3*d3*(d1+d2+(d3/2))))/((b1*d1)+(b2*d2)+(b3*d3));
c1=(d1+d2+d3)-c2;
I1=(pow(d1,3)*b1)/12+(pow(c2-(d1/2),2)*b1*d1);
I2=(pow(d2,3)*b2)/12+(pow((d1+(d2/2)-c2),2)*b2*d2);
I3=(pow(d3,3)*b3)/12+(pow((d1+d2+(d3/2)-c2),2)*b3*d3);
moi=I1+I2+I3;
double span, load, modulus, deltax, x;
ifstream inputfile;
inputfile.open(inputfilename);
if (!inputfile.eof())
{
inputfile >>span;
inputfile >>load;
inputfile >>modulus;
}
slope=((load*x)/(6*modulus*moi))*(3*pow(span,2)-(3*span*x)+pow(x,2));
return (slope); }
double slopec (double dinner, double douter, char inputfilename) {
double moi, slope;
moi=(3.1416/64)*(pow(douter,4)-(pow(dinner,4)));
double span, load, modulus, deltax, x;
ifstream inputfile;
inputfile.open(inputfilename);
if (!inputfile.eof())
{
inputfile >>span;
inputfile >>load;
inputfile >>modulus;
}
slope=((load*x)/(6*modulus*moi))*(3*pow(span,2)-(3*span*x)+pow(x,2));
return (slope); }
```