Write a Scala program to find a missing number in an array of integers

object scala_basic {
  def test(total_num: Int, numbers: Array[Int]) : Int = {  
   var total_num = 0;
   total_num = 7;
   var expected_num_sum = total_num * ((total_num + 1) / 2);
   var num_sum = 0;
   for (i <- 0 to  numbers.length-1){
    num_sum = num_sum + numbers(i);
   }
    (expected_num_sum - (num_sum));
  }  
  def main(args: Array[String]): Unit = {  
    var nums1 = Array(1,2,3,4,6,7)
    var array_total_nums = 7
    println("Original array:")
       for ( x <- nums1) {
         print(s"${x}, ")        
        }      
    println(s"\nTotal number in the array: ${array_total_nums}")
    println("\nMissing number of the said array:")
    println(test(array_total_nums, nums1));
    array_total_nums = 8
    var nums2 = Array(1,2,3,4,5,6,7)
    println("Original array:")
       for ( x <- nums2) {
         print(s"${x}, ")        
        }   
    println(s"\nTotal number in the array: ${array_total_nums}")
    println("\nMissing number of the said array:")
    println(test(array_total_nums, nums2));
}
}