Thread: gaussian elmination into fractions.

im supposed to send a data file containing values that look like this

Code:

3
2   3   1   11
4  -2   3    9
3   5  -3    4

the first value is put into variable N and the other numbers are put into an array to solve using the gaussian method. here's my code for FLOAT point numbers. i can solve it using FLOAT point numbers.

Code:

#include <iostream>
#include <fstream>
#include <iomanip>

ifstream infile;

void printEquation(float array[10][11], int N)
 {
  for (int i=0; i<N; i++)
   {
    for (int j=0; j<(N+1); j++)
     {
      if (j==0)
       { cout << endl;}
      cout << setw(10) << array[i][j];
      }  // for j
   }  // for i
 }
       
int main()
{
 char fileName[100], varName[10];
 int N, i, j, temp;
 float arr[10][11];

  for(i=0; i<10; i++) // sets variable names
   {
    varName[i] ='a'+i;
   }        

 cout << endl;
 cout << "Enter a filename to read the values from: ";
 cin >> fileName;


 infile.open(fileName);
 

 if (infile.fail())
  {
   cout << "Opening file " << fileName << " for input failed.  Goodbye" 
        << endl;
   exit(1);
  }

 infile >> N;

 cout << N << " Equations" << endl;
 if (N > 10)
  {
   cout << "Opening file " << fileName << " failed because the value N
that the file reads is greater than 10.  Check your data file.  Goodbye."
        << endl;
   cout << endl;
   exit(1);
  }

 for (i=0; i<N; i++)
  {
   for (j = 0; j<(N+1); j++)
    {
     infile >> temp;
     arr[i][j] = temp;
    }
  }

   printEquation(arr, N);

 for (int i = 0; i < N; i++) // for each column
  {
   cout << endl << "column " << i << ":" << endl;

  if (arr[i][i] !=0){
   float divisor = arr[i][i];

   for (int k=0; k < (N+1); k++)
     {arr[i][k] /= divisor;}
   }
   printEquation(arr, N);

   cout << endl;
   for (int j=0; j<N; j++) // for each row
    {
     if (j !=i)
      {
       float multiplier = arr[j][i];
       for (int k=0; k<(N+1); k++)
         arr[j][k] -= arr[i][k] * multiplier;
 
       cout << endl;
   printEquation(arr, N);

      }
    }

   }
 cout << endl;
       printEquation(arr, N);




/*
 for (i=0; i<N; i++)
   {
    cout << endl;
    cout << varName[i] << "=" << arr[0][N+1] << endl;
    cout << endl;
   }
*/

 cout << endl;
}

but for this assignment..im supposed to change all the numbers into fractions! this is what i've tried so far...and im getting millions of errors. please help!!

Code:

#include <iostream>
#include <fstream>
#include <iomanip>

ifstream infile;

class Fraction 
{

private:

  int numerator;
  int denominator;

public:

  Fraction()
   {
    numerator = 0;
    denominator = 1;
   }
  
  void setNumerator(int n)
   {
    numerator = n;
   }

  void dumpFraction()
   {
    cout.width(4);
    cout << numerator;
    if (denominator !=1)
      cout << "/" << denominator;
   }

  void div( Fraction divisor )
   {
    numerator *= divisor.denominator;
    denominator *= divisor.numerator;
   }

  void mult( Fraction multiplier)
   {
    numerator /= multiplier.denominator;
    denominator /= multiplier.numerator;
   }

}; // class Fraction

void printEquation(Fraction array[10][11], int N)
 {
  for (int i=0; i<N; i++)
   {
    for (int j=0; j<(N+1); j++)
     {
      if (j==0)
       { cout << endl;}
      cout << setw(10) << array[i][j];
      }  // for j
   }  // for i
 }
       
int main()
{
 
 char fileName[100], varName[10];
 int N, i, j, temp;
 Fraction arr[10][11];

  for(i=0; i<10; i++) // sets variable names
   {
    varName[i] ='a'+i;
   }        

 cout << endl;
 cout << "Enter a filename to read the values from: ";
 cin >> fileName;


 infile.open(fileName);

 if (infile.fail())
  {
   cout << "Opening file " << fileName << " for input failed.  Goodbye" 
        << endl;
   exit(1);
  }

 infile >> N;

 cout << N << " Equations" << endl;
 if (N > 10)
  {
   cout << "Opening file " << fileName << " failed because the value N
that the file reads is greater than 10.  Check your data file.  Goodbye."
        << endl;
   cout << endl;
   exit(1);
  }

 for (i=0; i<N; i++)
  {
   for (j = 0; j<(N+1); j++)
    {
     infile >> temp;
     arr[i][j].setNumerator(temp);
    }
  }

   printEquation(arr, N);


 for (int i = 0; i < N; i++) // for each column
  {
   cout << endl << "column " << i << ":" << endl;

  if (arr[i][i] !=0)
  {
   Fraction divisor = arr[i][i];

   for (int k=0; k < (N+1); k++)
     {
      arr[0][k].div(divisor);
     }
   }
   printEquation(arr, N);

   cout << endl;
   for (int j=0; j<N; j++) // for each row
    {
     if (j !=i)
      {
       Fraction multiplier = arr[j][i];
       for (int k=0; k<(N+1); k++)
         arr[j][k] -= arr[i][k] * multiplier; 
       cout << endl;
   printEquation(arr, N);

      }
    }

   }
 cout << endl;
       printEquation(arr, N);




/*
 for (i=0; i<N; i++)
   {
    cout << endl;
    cout << varName[i] << "=" << arr[0][N+1] << endl;
    cout << endl;
   }
*/

 cout << endl;
}

Haven´t quite read your code, but, you don´t mention what is your problem. Compiler errors? Malfunctions? What?