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JavaScript Introduction to Programming Objects and Arrays Arrays

Mike Zhu
Mike Zhu
1,840 Points
Posted by Mike Zhu
Mike Zhu
1,840 Points

Why can not use such description like "for (int i = 0; i < friends.length; i++)"in the loop

When I try to use for (int i = 0; i < friends.length; i++), it just cannot run the loop. I have to use for (var i = 0; i < friends.length; i++)

Is it because in Javascript, int i = 0, is just a constant? Only var i = 0, is a variable?

2 Answers

chrisp
chrisp
13,686 Points

HI Mike,

Of course, no problem. You're very welcome :).

Yes you're right. In JavaScript 'int' is not really a datatype, but its more of a reserved word.

Unlike other programming languages, reserved words like 'int', 'long'. 'float', etc... are reserved words that are currently not use.

In later version of javascript, I remember that 'int' is no longer a reserved word and has been taken out and therefore is best to avoid using it.

Here is a list of javascript reserve words http://msdn.microsoft.com/en-us/library/ie/0779sbks(v=vs.94).aspx

Here is a list of datatypes http://msdn.microsoft.com/en-us/library/ie/7wkd9z69(v=vs.94).aspx

Best of luck with Javascript,

chrisp
chrisp
13,686 Points
chrisp
chrisp
13,686 Points

I think when you are using 'int' with 'i' it returns false because 'i' is not an integer and int doesn't really store anything. Javascript would get confuse when 'i' hasn't been introduce or define.

var is the way to go since it can hold many datatypes.

In most cases in javascript nothing is constant as in a variable that cannot be changed. Defining Const is still a draft version for ECMAScript 6. I am not sure if browser are currently supporting it.

Mike Zhu
Mike Zhu
1,840 Points
Mike Zhu
Mike Zhu
1,840 Points

Thank you so much! But in other programming languages, such as Java or Objecttive-C, the for-loop goes like, int i = 0; i < 5; i++. I am so confused that, just like you said, "i" is not an integer, so, you mean, in Javascript, "int" in not a data type for integer, is that right? Because in other languages, "int" stands for the data type of an integer.

I am completely new in Javascript and thanks for your answer!