Question

According to the tutorial I am reading, the program below displays “Hello Ima Reader.”

I have one question about this program. Why does it, in its final line, insert a “2” into alert(name[2])?

When the function is called in the second last line, it only passes “name”, but when the alert is run it uses a “2”. I’m assuming that 2 refers to the length of name, but is it necessary? If so, Why?

function makeHello(name) {
   name[name.length] = "Hello" + name [0] + " " + name[1];
}

var name = new Array ('Ima', 'Reader');
makeHello(name);
alert(name[2]); 

Answer 1

The line var name = new Array ('Ima', 'Reader'); creates an array called name with element 0 set to "Ima" and element 1 set to "Reader".

The next line, makeHello(name);, invokes the makeHello function which creates an element 2 in the name array set to "Hello Ima Reader".

The last line, alert(name[2]); merely displays the element 2 that was created by the makeHello function.