Member Avatar for vrga

I am having trouble reading the second matrix from my file. Can anyone help me please? Thank you!

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{   
	ifstream in;
    ofstream out;
	int num1, num2, num3;
	
	
	int i = 0;
	int counter = 0;
   
	vector < vector <int> > MatrixA;
    vector < int > RowA; 
	
	vector < vector <int> > MatrixB;
    vector < int > RowB; 
    
	in.open ( "j:\\input1.txt" );

	if ( !in )
	{
	cout << "Input file ( input1.txt ) does not exit." << endl;
	return 1;
	system ( "pause" );
	}

	
	while (in)
	{
	
	for (i =0; i<9; i++){

	in >> num1 >> num2 >> num3;
	{
    RowA.push_back(num1);
	RowA.push_back(num2);
	RowA.push_back(num3);
    MatrixA.push_back(RowA);
	RowA.clear();
	
	}
	
}
	
	for (i=0; i < 9; i++){

    in >> num1 >> num2 >> num3;
	{
    RowB.push_back(num1);
	RowB.push_back(num2);
	RowB.push_back(num3);
    MatrixB.push_back(RowB);
	RowB.clear();
	}
 }
}
		
	
    for(int i=0; i<3; i++){
    for(int j=0; j<3; j++){
    cout << MatrixA[i][j]; 
    }
    cout << endl;
}

    for(int i=0; i<3; i++){
    for(int j=0; j<3; j++){
    cout << MatrixB[i][j]; 
    }
	cout << endl;
}


   cout << endl; 
   cout << "Vector size: " << MatrixA.size() << endl << endl;
   cout << "Vector size: " << MatrixB.size() << endl << endl;
	
	//outfile.open ( "j:\\output.txt" );
  	cout << "Processing data......." << endl;
    system ("pause");

	

	in.close();
	out.close();
    return 0;
}
  • 3 Contributors
  • 5 Replies
  • 112 Views
  • 3 Days Discussion Span
  • Latest Post Latest Post by vrga
Member Avatar for stilllearning

What does the sample data in your file look like ?

Regarding your code, you need to be careful about the loop which is reading from your file. Unless your total number of records in the file is a multiple of 9 you will not read the values into the vectors correctly. Its likely you will keep looping for values even after you reach eof ..

Member Avatar for vmanes

Just how big are your matrices supposed to be? What is the input data. From your code, I see two sizes:

for (i =0; i<9; i++)
       {

	in >> num1 >> num2 >> num3;
	{
          RowA.push_back(num1);
	  RowA.push_back(num2);
	  RowA.push_back(num3);
          MatrixA.push_back(RowA);
	   RowA.clear();
	
	}
	
      }
	
		
	
    for(int i=0; i<3; i++)
   {
       for(int j=0; j<3; j++)
      {
          cout << MatrixA[i][j]; 
       }
    }

The input portion read in 9 x 3 values, for a total of 27. The output only displays a 3 x 3 matrix.

Which is it?

Member Avatar for vmanes

Since you are reading in 3x3 matrices, your loops should do just that. You have one input statement reading three values, so loop that just three times, not nine.

Member Avatar for vrga

Thank you very much! :icon_razz:

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