Closures/Value capture: Difference between revisions

=={{header|Swift}}==

The naive way using a C-style for loop does not work, since Swift captures variables by reference, and one variable is changed over the course of the loop:

for var i = 0; i < 10; i++ {

funcs.append({ i * i })

However, using a foreach loop over a range does work, since you get a new constant variable every iteration:

funcs.append({ i * i })

}

The C-style for loop can also work if we assign it to a local variable inside the loop:

for var i = 0; i < 10; i++ {

let j = i

Alternately, we can also use <code>map()</code> to map over a range, and create the squaring closure inside the mapping closure which has the integer as a parameter:

println(funcs[3]()) // prints 9</lang>