why i get this syntax error

in this line

Code:

---

printf("%d",mat[index][kndex]);

---

i get

|36|error: invalid use of array with unspecified bounds|

Perhaps because you put a space between the first dimension, and the second. :)

Santa will give you a piece of C coal for that one! :p :p

no its not a space because when i tried to delete this space i delete "]"
there is no space between them

Post the smallest and simplest program that demonstrates the error.

Code:

---

void display(int mat[][],int rows,int cols){

    int index,kndex;

        for (index=0;index<rows;index++){

          for (kndex=0;kndex<cols;kndex++){

            printf("&#37;d ",mat[index][kndex]);
          }
          printf("\n");
        }
    }//end display

---

So the error is on the line that says

Code:

---

void display(int mat[][],int rows,int cols){

---

When passing arrays to a function, all dimensions (except possibly the first) must be given in the function declaration.

but my matrix size is set by the user.

i cant put numbers in [][]

How are you declaring your matrix then? You may have to do the array indexing "by hand", then.

so in the signature i have to write something like:

Code:

---

void display(int mat[3][4],int rows,int cols){

---

i dont want to declare it
i want to input a matrix with numbers that the user inputed

Obviously you have to declare any variable you intend to use.

can i build a new matrix
and make reference to the input one?

tried this still not working

Code:

---

void display(int mat[][],int rows,int cols){

    int index,kndex;
    int mat2[rows][cols];

    mat2[][]=mat[][];

        for (index=0;index<rows;index++){

          for (kndex=0;kndex<cols;kndex++){

            printf("&#37;d ",mat2[index][kndex]);
          }
          printf("\n");
        }
    }//end display

---

i get a different error

|33|error: syntax error before ']' token|

You still can't pass mat[][] into a function. If you don't know the size of the array, you can only pass it in as a pointer-to-int, not as an array.

but array is a pointer
it decays and give the first value

i want to input an array which the user chose to the function
how do i do that?

Just like you said. The array name will decay to a pointer. But the function must accept a pointer-to-int, not some nonexistent "[][]" thing.