import java.text.DecimalFormat;

class MatrixLib
{
    // Method to read a matrix of integers, of specified dimension.
    
    public static int[][] readIntMatrix( int numRows, int numCols )
    {
        int row;         // row  index
        int col;         // column index
        int[][] matrix;  // result

        matrix = new int[numRows][numCols];
        System.out.println( "Enter a matrix, one row at a time" );
        System.out.print( "for " + numRows + " rows, with " );
        System.out.println( numCols + " entries per row: ");

        for ( row = 0; row < numRows; row = row + 1 )
        {
            matrix[row] = ITI1120.readIntLine( );
        }
        return matrix;
    }

    // Method to read a matrix of doubles, of specified dimension.
    
    public static double[][] readDoubleMatrix( int numRows, int numCols )
                                         throws java.io.IOException
    {
        int row;         // row  index
        int col;         // column index
        double[][] matrix;  // result

        matrix = new double[numRows][numCols];
        System.out.println( "Enter a matrix, one row at a time" );
        System.out.print( "for " + numRows + " rows, with " );
        System.out.println( numCols + " entries per row: ");

        for ( row = 0; row < numRows; row = row + 1 )
        {
            matrix[row] = ITI1120.readDoubleLine( );
        }
        return matrix;
    }
    
    // Method to print a matrix of integers with nice formatting.
    
    public static void printMatrix( int[][] matrix )
    {
        int row;         // row  index
        int col;         // column index

        for ( row = 0; row < matrix.length; row = row + 1 )
        {
            // Print entries in row
            
            for ( col = 0; col < matrix[row].length; col = col + 1 )
            {
                System.out.print( format( matrix[row][col] ) + " " );
            }
            System.out.println( );
        }        
    }

    // This method takes a value of type int, and returns a String
    // that contains the value of the int, but formatted to have width
    // of exactly 5 characters.

    // Use:  get numbers to line up in columns
    
    public static String format( int value )
    {
        String result;
        DecimalFormat df;
        int numBlanks;

        // The following requests numeric output with exactly one decimal
        // place, and at least one but no more than two digits to the left
        // of the decimal point.  See java.text.DecimalFormat.
        
        df = new DecimalFormat( "####0" );

        // The next line actually does the formatting, and produces a String.
        
        result = df.format( value );

        // The following makes sure that the String has exactly 5 characters
        // (needed to space columns evenly) and adds blanks to the front if
        // needed.  Class DecimalFormat ought to do this, but...
        
        numBlanks = 5 - result.length( );
        for ( int index = 1; index <= numBlanks; index++ )
        {
            result = " " + result;
        }
        
        return result;
    }

}