# Kotlin Program to Multiply to Matrix Using Multi-dimensional Arrays

For matrix multiplication to take place, the number of columns of first matrix must be equal to the number of rows of second matrix. In our example, i.e.

`c1 = r2`

Also, the final product matrix is of size `r1 x c2`, i.e.

`product[r1][c2]`

You can also multiply two matrices using functions.

## Example: Program to Multiply Two Matrices

``````fun main(args: Array<String>) {
val r1 = 2
val c1 = 3
val r2 = 3
val c2 = 2
val firstMatrix = arrayOf(intArrayOf(3, -2, 5), intArrayOf(3, 0, 4))
val secondMatrix = arrayOf(intArrayOf(2, 3), intArrayOf(-9, 0), intArrayOf(0, 4))

// Mutliplying Two matrices
val product = Array(r1) { IntArray(c2) }
for (i in 0..r1 - 1) {
for (j in 0..c2 - 1) {
for (k in 0..c1 - 1) {
product[i][j] += firstMatrix[i][k] * secondMatrix[k][j]
}
}
}

// Displaying the result
println("Product of two matrices is: ")
for (row in product) {
for (column in row) {
print("\$column    ")
}
println()
}
}``````

When you run the program, the output will be:

```Product of two matrices is:
24    29
6    25    ```

In the above program, the multiplication takes place as:

```|-    (a11 x b11) + (a12 x b21) + (a13 x b31)    (a11 x b12) + (a12 x b22) + (a13 x b32)    -|
|_    (a21 x b11) + (a22 x b21) + (a23 x b31)    (a21 x b12) + (a22 x b22) + (a23 x b32)    _|
```

In our example, it takes place as:

```|-    (3 x 2) + (-2 x -9) + (5 x 0) = 24    (3 x 3) + (-2 x 0) + (5 x 4) = 29    -|
|_    (3 x 2) + ( 0 x -9) + (4 x 0) = 6    (3 x 3) + ( 0 x 0) + (4 x 4) = 25    _|
```

Here's the equivalent Java code: Java program to multiply two matrices