# exjl3.jl  declare and print variable, vector, matrix
using Printf  # only needed if  @printf  will be used

println("julia exjl3.jl running")

s1 = "any string"
println(s1)
s2 = "more"
println(s2)
s3 = s1*s2  # concatenation
println(s3)
s4 = s1*" "*s2  # space between strings
println(s4)

i = 13         # integer  Int
print("i = ")
print(i)       # print can print everything, even arrays
println(" ")   # no line feed in just  print
@printf "i = %d \n" i   # "C" format and list

x = 0.0        # double  Float64
@printf "x=%f \n" x
for i in 1:4
  global x
  x = x + 1.0
end
@printf "x=%f \n" x


v1 = [ 1 2 3 4 ]  # row vector  no comma
print("v1=")
print(v1)
print("  row vector");
println(" ")
@printf "v1[3]=%d \n" v1[3]

v2 = [1, 2, 3, 4]  # typical row vector
print("v2=")
print(v2)
print("  with ,  row vector");
println(" ")
@printf "v2[3]=%d \n" v2[3]

v3 = [ 1 2 3 4 ]' # column vector "'"
print("v3=")
print(v3)
print("  with '  column vector");
println(" ")
@printf "v3[3]=%d \n" v3[3]

# matrix
A = Array{Float64,2}(undef, 2, 3)
println("A created ")
print("A=")
print(A)
println(" ")

A0 = zeros(2, 3)
print("A0=")
print(A0)
println(" ")

A1 = ones(2, 3)
print("A1=")
print(A1)
println(" ")

B = [1.0 2.0 3.0 ; 4.0 5.0 6.0] # no commas!  ; or new line
print("B=")
print(B)
println(" ")

nrow = size(B,1)
print("nrow=size(B,1)=")
println(nrow)
ncol = size(B,2)
print("ncol=size(B,2)=")
println(ncol)
println(" ")

println("exjl3.jl finished")
# end exjl3.jl