newbie needs help with lesson 3: loops

in lesson 3 where says x++ in the example, what does the ++ bit do to x?

x++ means increment x. If x is 5, the result of x++ is 6.

it increments!

suppose we have a variable " Length "

Length++

is just like writing

Length = Length + 1

increment means adding 1 to the variable, so if

Length = 25

then we type

Length++

then the value of Length is now 26

Another shorthand way of doing this is to say:

Length+=1;

It'll take the current value of length and add whatever you specify to it. Just make sure before you use any of these methods that length is initialized.

Also legal is ++length. It does the same thing. The only difference is that the value ++length returns is after it increments length, which length++ just returns length.

Here's some example code to help you out:

Code:

---


int x = 5;

x++; // Line A
// x is now 6 

++x; // Line B
// x is now 7

int y = x++; // Line C
// x is 8, y is 7 (the OLD value of x).

int z = ++x; //Line D
// x is 9, z is 9 (the NEW value of x).

---

If your code does not need the return value, use ++x not x++.
I.e. instead of Line A's syntax, use Line B's.

The reason? ++x is always at least as efficient as x++ and sometimes more efficient. The reason is that x++ has to return an old, temporary value. In certain cases, the compiler can optimize away the unused temporary, but not always.

So, as a rule, if either will work, use ++x not x++, it's a better habit to be in.

So, write your for loops like:

for (int x = 0; x < 10; ++x)

which looks a little unusual but is a better habit to be in.