// version 1.0.6

fun main(args: Array<String>) {
    print("Enter size of matrix : ")
    val n = readLine()!!.toInt()
    println()
    val identity = Array(n) { IntArray(n) } // create n x n matrix of integers

    // enter 1s in diagonal elements
    for(i in 0 until n) identity[i][i] = 1

    // print identity matrix if n <= 40
    if (n <= 40)
        for (i in 0 until n) println(identity[i].joinToString(" "))
    else
        println("Matrix is too big to display on 80 column console")
}