“类型“（）”不符合协议“序列类型”

Question

I am following an online class but my professor is using a different version of Xcode. I have version 7.2.1. It asked me to put parentheses after arr in the second line, but when I do, it says "Type "()" does not conform to protocol SequenceType . I don't know how to fix it. Thanks.

var arr = {1; 2; 3; 4}    
for i in arr() {    
    print(i)
}

Answer 1

Your array declaration needs to use brackets and commas.

var arr = [1, 2, 3, 4]

for i in arr {
    print(i)
}

Answer 2

Another way to write the same way is using below:-

half-open range operator (..<)

let arr = [1, 2, 3, 4]
for i in 0..<arr.count 
{
 print(arr[i])
}

closed range operator (...)

let arr = [1, 2, 3, 4]
for i in 0...arr.count-1 
{
 print(arr[i])
}