Akhil assignment 0

//CS-620 programming Assignment 0 by Akhil Bandari.Date: 30-01-2-15.

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>

void main(int argc , char *argv[])

{
    //Check file is supplied or not
    if (argc!=2)
    {

        printf("Error!.Filename is missing\n");
    }

    //If file is supplied go on....

    else
    {
        //File handling code goes here
        FILE *file = fopen( argv[1], "r");

        //Check whether file opened correctly or not
        if(file == 0)
        {
            printf("Couldn't open file. Give correct file.\n");

        }
        //If opened correctly start process of building matrices
        else
        {
               //Create tools for reading from file

               size_t len = 0;
               ssize_t read;
               char * line = NULL;
               char *split;
               const char*s = "\t";
               int line_number = 0, n_by_n , n_minus_one_by_n_minus_one , drop_row_column, i , j;

               //Declare matrices of type double
               //A -original Matrix
               //B -modified Matrix

               double **A,**B ;


               while ((read = getline(&line, &len, file)) != -1)
               {
                    line_number+=1;

                    //If it is a beginning line of file
                    if (strlen(line) == 2 && line_number == 1)
                    {
                            n_by_n =  atoi(line);

                            //Allocating memory for original matrix A

                            A = (double **)malloc(n_by_n * sizeof(double));

                            for (i=0; i<n_by_n; i++)
                            {
                                A[i] = (double *)malloc(n_by_n * sizeof(double));
                            }
                    }

                    //else it is a Matrix row
                    else if(strlen(line) > 2)
                    {


                            /* get the first token */
                               split = strtok(line, s);
                               i = line_number - 2;
                               j = 0;

                            /* walk through other tokens */
                            while( split != NULL )
                            {
                                  //Store each splitted token into Matrix A
                                  A[i][j] = atof(split);
                                  j++;
                                  split = strtok(NULL, s);
                            }

                    }

                    //It is the last line of file.Here start building Matrix B
                    else if(strlen(line) == 2)
                    {

                        n_minus_one_by_n_minus_one = n_by_n -1 ;

                        drop_row_column = atoi(line);

                        //Allocating memory for matrix B
                        B = (double **)malloc(n_minus_one_by_n_minus_one * sizeof(double));

                        for (i=0; i<n_minus_one_by_n_minus_one ; i++)
                        {
                                B[i] = (double *)malloc(n_minus_one_by_n_minus_one * sizeof(double));
                        }

                        //Copy values of Matrix A into Matrix B dropping the required row and column



                        for (i = 0 ; i < n_by_n ; i++)
                        {
                            if (i != drop_row_column)
                            {
                                for (j = 0 ; j < n_by_n ; j++)
                                {
                                    if (j != drop_row_column)
                                    {
                                        if (i < drop_row_column && j < drop_row_column)
                                            B[i][j] = A[i][j];
                                        else if (i < drop_row_column && j > drop_row_column)
                                            B[i][j-1] = A[i][j];
                                        else if (i > drop_row_column && j < drop_row_column)
                                            B[i-1][j]=A[i][j];
                                        else
                                            B[i-1][j-1]=A[i][j];
                                    }
                                }
                            }
                        }
                    }

               }

          //Beginning the printing of formatted output
          printf("Length: %d\n",n_by_n);
          printf("Original matrix:\n");

         //loop through original Matrix A
          for (i = 0 ; i <  n_by_n ; i++)
          {
                for (j = 0; j < n_by_n; j++)
                {
                    printf("%.4lf   ", A[i][j]);
                }
                printf("\n");
          }

          printf("Deleting row and column %d\n",drop_row_column);

          printf("New matrix:\n");
          //loop through newly created matrix B

          for (i = 0 ; i <  n_minus_one_by_n_minus_one ; i++)
          {
                for (j = 0 ; j < n_minus_one_by_n_minus_one ; j++)
                {
                    printf("%.4lf   ", B[i][j]);
                }
                printf("\n");
          }


         //Close the file for house keeping
         fclose(file);

        }
    }
}