Thread: simple matrix

Just a simple misunderstanding -> To be fair, I'm not well known for my verbal skills :P

Okay so I've modified my code
I now want it to work like this

Code:

cmd> A 2 2 1 2 3 4
(where A is the name of the matrix it is assigned to and 2 2 are the rows and columns and 1 2 3 4 are the elements of the matrix)
displays matrix
cmd> A 2 2 3 4 5 6 
(new matrix A displayed)

so "cmd>" is kind of this thing awaiting my order. Further on I plan on letting the user even enter a second matrix B


So this is what I came up with. If there is some other way of writing cmd> without using strings and that is more easier please let me know. I dont want to end up jumbling strings arrays and pointers.

Code:

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


#define MAX_CMD_LEN 25


void matrix_display(int *matrix, int row_count, int column_count);


int main (void)
{
  int row_size1,col_size1,row_size2,col_size2;
  int **A;
  int i = 0, j = 0, flag =1;
  char a;
  char command[MAX_CMD_LEN];
  char *p;


   do{
    printf("\ncmd> ");


    if(fgets(command,  MAX_CMD_LEN, stdin) != NULL){
      if((p = strchr( command, '\n')) != NULL)
        *p = '\0';
    }
    if(command[0] == 'A'){


printf("Enter the elements of the first matrix write 99 when done:");
scanf("%d %d",&row_size1,&col_size1);


  A= malloc(row_size1*sizeof(int*));
  for(i=0;i<row_size1;i++)
    {
      A[i]=malloc(col_size1*sizeof(int));
    }


  for(i=0;i<row_size1;i++)
    {
      for(j=0;j<col_size1;j++)
        {
          scanf("%d",&A[i][j]);
   }
           }


matrix_display(A, row_size1, col_size1);
}
}
   
while (flag ==1);
return 0;
}

void matrix_display(int *matrix, int row_size1, int col_size1)
{
  int i,j;

printf("matrix  is\n");
for(i=0;i<row_size1;i++)
    {
      for(j=0;j<col_size1;j++)
      printf("%d ", matrix[i][j]);
      printf("\n");
    }

for(i=0;i<row_size1;i++)
    {
      free(matrix[i]);
    }
 free(matrix);

OK - I'm going to give you back you code with good indentation - It will be very obvious that you have not got your braces right. Copy and paste this code into where ever you are coding from and try to keep it consistent with this

Code:

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




#define MAX_CMD_LEN 25




void matrix_display(int *matrix, int row_count, int column_count);




int main (void)
{
    int row_size1,col_size1,row_size2,col_size2;
    int **A;
    int i = 0, j = 0, flag =1;
    char a;
    char command[MAX_CMD_LEN];
    char *p;




    do
    {
        printf("\ncmd> ");




        if(fgets(command,  MAX_CMD_LEN, stdin) != NULL)
        {
            if((p = strchr( command, '\n')) != NULL)
                *p = '\0';
        }
        if(command[0] == 'A')
        {




            printf("Enter the elements of the first matrix write 99 when done:");
            scanf("%d %d",&row_size1,&col_size1);




            A= malloc(row_size1*sizeof(int*));
            for(i=0; i<row_size1; i++)
            {
                A[i]=malloc(col_size1*sizeof(int));
            }




            for(i=0; i<row_size1; i++)
            {
                for(j=0; j<col_size1; j++)
                {
                    scanf("%d",&A[i][j]);
                }
            }
        }




        matrix_display(A, row_size1, col_size1);
    }
}


while (flag ==1);
return 0;
}


void matrix_display(int *matrix, int row_size1, int col_size1)
{
    int i,j;


    printf("matrix  is\n");
    for(i=0; i<row_size1; i++)
    {
        for(j=0; j<col_size1; j++)
            printf("%d ", matrix[i][j]);
        printf("\n");
    }


    for(i=0; i<row_size1; i++)
    {
        free(matrix[i]);
    }
    free(matrix);

Add this to after your printf statement

Code:

    do
    {
        printf("\ncmd> ");
        fflush(stdout); 

Isnt fflush a C++ reference?

no.

fgets puts everything up to the '\n' character into the array called "command" -> Nothing will be left on the stdin (buffered input from the keyboard), so you can't use any of the scanf's to read the command line any more.

You need to decide if you want to put the command line into the array as a string and work with that, or leave everything on stdin and get them one at a time.

In the code from post #37/#34/#33 you are already doing it with the fgets statement.

If it were up to me, I'd use the fgets and then go through each entry using strtok - But this might be a bit of a learning curve for you

You are probably better getting rid of the fgets and replacing it with getchar, as it will only get the first character off stdin -> If it is 'A', then scanf for the two size integers, and then scanf for each element integer after that.