Ok, I have ripped out my hair trying to solve this. I am having problems getting

Question

Ok, I have ripped out my hair trying to solve this.  I am having problems getting a C++ program that I am writing to work properly.  I have traced the problem to this small piece of program.  Can anyone help me to figure out how to get this thing to increment correctly.  Here's what I have so far:

#include <iostream>     //pre-processor directs - iostream talks to screen
#include <iomanip>      //pre-processor directs - string
#include <cmath>     // allows math functions
using namespace std;
const int size=100;
int main ( void )
{
              
              double x[size], y[size];
              double L = 2.0, I = 7.29167e-8, E = 2.05e+11;
              int N = 10, W = 125;
                                                                 
                for (int i=0;i<L;i++)     //initiates, defines and sets counter
                    x[i]=(i*(L/N));       //initiates the first value of the array
                                             
                    cout<<" This program has calculated the deflection of the beam";
                    cout<<" from the information supplied by you."<<endl;

                    cout<<" Distance from end of beam: x(m) "<<"   Deflection: d(m)";        //prints column headers to screen
                    cout<<" ------------------------------------------------------------"<<endl;
                
                for (int i=0;i<L;i++)                //initiates, defines and sets counter
                  
                  y[i]=(-W/(6*E*I))*(pow(x[i],3)-3*pow(L,2)*x[i]+2*pow(L,3));    //calculates beam deflection
    
                for (int i=0;i<N;i++)
                               //initiates, defines and sets counter
                  cout<<setiosflags(ios::scientific)<<setprecision(2)<<setw(10)
                  <<x[i]<<setprecision(2)<<setw(35)<<y[i]<<endl;//prints values in arrays to screen
                  cout<<endl;
                  
system("pause");
return 0;
}

This is what my result should be.  

Distance from end of beam: x(m)    Deflection: d(m)

0.000E+00                                       -2.230E-02

2.000E-01                                        -1.897E-02

4.000E-01                                        -1.570E-02

6.000E-01                                        -1.257E-02

8.000E-01                                        -9.633E-03

1.000E+00                                       -6.969E-03

1.200E+00                                       -4.638E-03

1.400E+00                                       -2.709E-03

1.600E+00                                       -1.249E-03

1.800E+00                                       -3.233E-04

2.000E+00                                        0.000E+00

I get nothing like it.  Any help would be appreciated.

Explanation / Answer

The problem is contained in your for loops.

for (int i=0;i<L;i++) //initiates, defines and sets counter
x[i]=(i*(L/N)); //initiates the first value of the array

and

for (int i=0;i<L;i++) //initiates, defines and sets counter
y[i]=(-W/(6*E*I))*(pow(x[i],3)-3*pow(L,2)*x[i]+2*pow(L,3)); //calculates beam deflection

Since L is 2.0 it stops after 2, which is the reason why the first and second rows of the table is correct while the rest is all a hot mess. Just change the i<L to i<=N in both of those for loops and it will produce the exact table you want it to, with a bit of rounding error(change your setprecision to 3 instead to fix). You'll need to change the printing for loop to i<=N as well if you want the very last line.

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