Thread: Defining a Matrix ..

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At least attempting couldn't hurt...

Code:

print "Enter the no. of ROW"
read ROW

print "Enter no. of COLUMN"
read COLUMN

for i < ROW
    for j < COLUMN
       read a[i][j]
       
print "This is what you entered"

for i < ROW
   for j < COLUMN
      print a[i][j]

That is how you should go ahead on doing this. So can you now take that pesudo code and implement it?

-ssharish

Originally Posted by ssharish2005

So can you now take that pesudo code and implement it?

That pseudo code does not match the OP's specs, I would say!

Have a look at this:

Code:

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

void showmatrix (int *matrix[], int rows, int cols) {   /* generalized function */
        int i, ii;    
        for (i=0; i<rows; i++) {
                for (ii=0; ii<cols; ii++) printf("%5d", matrix[i][ii]);
                printf("\n");
        }
}

int main() {
        int size, **matrix, i, ii; 
        printf("Size of matrix: ");
        scanf("%d",&size);
        matrix = malloc(size*sizeof(int*)); /* allocate for rows of int POINTERS */
        for (i=0; i<size; i++) {
                matrix[i]=malloc(size*sizeof(int)); /* allocate for columns of INTS */
                printf("Data for row %d: ",i+1);
                for (ii=0; ii<size; ii++) {
                        scanf("%d",&matrix[i][ii]);
                }   
        }
        showmatrix(matrix,size,size);
        return 0;
}

Tested, -Wall, works (enter the row data as numbers separated by spaces).

The most important thing for you to understand is the use of malloc; a dynamic matrix is actually an array of pointers; each pointer represents a row.

This does not error check the user data!

And the most important thing YOU can learn is to stop doing the whole goddamn thing for people who don't do anything!

Quzah.

Originally Posted by MK27

That pseudo code does not match the OP's specs, I would say!

Have a look at this:

Code:

#include <stdio.h>
#include <stdlib.h>
 
void showmatrix (int *matrix[], int rows, int cols) {   /* generalized function */
        int i, ii;    
        for (i=0; i<rows; i++) {
                for (ii=0; ii<cols; ii++) printf("%5d", matrix[i][ii]);
                printf("\n");
        }
}
 
int main() {
        int size, **matrix, i, ii; 
        printf("Size of matrix: ");
        scanf("%d",&size);
        matrix = malloc(size*sizeof(int*)); /* allocate for rows of int POINTERS */
        for (i=0; i<size; i++) {
                matrix[i]=malloc(size*sizeof(int)); /* allocate for columns of INTS */
                printf("Data for row %d: ",i+1);
                for (ii=0; ii<size; ii++) {
                        scanf("%d",&matrix[i][ii]);
                }   
        }
        showmatrix(matrix,size,size);
        return 0;
}

Tested, -Wall, works (enter the row data as numbers separated by spaces).

The most important thing for you to understand is the use of malloc; a dynamic matrix is actually an array of pointers; each pointer represents a row.

This does not error check the user data!

And the code which you've is after all a memory leak!

-ssharish