// exgl3.go  example  declare and use variables, arrays, matrix
package main

import("fmt")

func main() {
  fmt.Println("go run exgl3.go  running")

  var y float64
  y = 123.4 + 0.05
  fmt.Println("y=", y)
  
  // Here we create an array a that will hold exactly 5 ints.
  // The type of elements and length are both part of the array’s type.
  // By default an array is zero-valued, which for ints means 0s.
  var ai [5]int
  fmt.Println("array ai:", ai)

  var x [3]float64
  fmt.Println("array x:", x)
    
  // We can set a value at an index using the array[index] = value
  ai[4] = 100
  fmt.Println("modified:", ai)
  fmt.Println("ai[4]=", ai[4])

  x[0] = 1.1
  x[1] = 2.2
  x[2] = 3.3
  fmt.Println("array x:", x)
    
  // The builtin len returns the length of an array.
  fmt.Println("len(ai)=", len(ai))

  // Use this syntax to declare and initialize an array in one line.
  b := [5]int{1, 2, 3, 4, 5}
  fmt.Println("array b:", b)

  // multi-dimensional data structures.
  var twoD [2][3]int
  for i := 0; i < 2; i++ {
    for j := 0; j < 3; j++ {
      twoD[i][j] = i + j
    }
  }
  fmt.Println("twoD= ", twoD)

  m1 := [2][2]float64{{1.1, 1.2},{2.1, 2.2}}
  fmt.Println("matrix m1= ", m1)
  
  fmt.Println("exgl3.go finished")
}