. 11 The For Statement
The 
.Key for statement
is a very important statement to learn.
We use it in just about every real program we write.

The for loop is for counting..... we can use while for other loops.
. Previous -- Fundamental Control Structure
.See ./10.html
.Open Prepare
. 5.1 Introduction
. 5.2 Essentials of Counter-Controlled Repetition
. 5.3 for Repetition Statement
. 5.4 Examples Using the for Statement
. Common Programming Error 5.7
We do our taxes using a spreadsheet that I wrote.... and entered
the numbers rounded to whole dollars.  The spreadsheet did the
computation using a version of double length but displayed the
answer on the screen as whole numbers.  We copied these into the
form and sent it off to the IRS.

The sent us back a check for $1.   The rounding introduced a difference
in the taxes.  Since then my wife checks every calculation by hand.  She
doesn't trust the computer or the programmer.
. Using stream manipulators to format numerical output
Neat stuff....
.Close Prepare
. Deliver a question
.Open Questions and Answers
. Explain the initialization continuationCondition and increment in a for loop
A for loop always has precisely three parts plus a body:
.As_is 		for(A; B; C ) D
`A` is the initialization part is is executed before the loops start.  The `B`
is the continuation condition and means that the loop will execute if its value
is true.  Then it executes the body `D`, followed by the increment `C`.  Finally it
returns to the condition `B` and tests it again...   The pattern
is
	A (B D C B D C B D C ... ) !B

In effect the above
for loop does the exact same thing as this set of more complex code:
.As_is 		{
.As_is 			A;
.As_is 			while(B)
.As_is 			{
.As_is 				D;
.As_is 				C;
.As_is 			}
.As_is 		}
(The braces are necessary).
. Explain scope
The scope of a variable or other name is the parts of the program where
it has a particular meaning.  It is always determine by the braces in the
program.   It starts where the name is declared and runs down to the
closing brace that matches the opening brace that surrounds the declaration.

If the same identifier is declared in different places then it gets different
meanings.

If a variable or function is redeclared in an inner block {...}
then there is a `hole` in its scope.  The different meaning hold in the
`hole`.

. Are there different kinds of break statements
No.
 The same type of statement has different effects inside a loop to a switch.

. How many breaks in a program
As many as you need. 

But beware getting confused between breaking out of a loop and a
surrounding switch.

. How do you get rid of the ./ in executing a program in UNIX
You need to put "." (the current directory) in your shell PATH
variable.  Something like this
.As_is PATH=$PATH:.
needs to be put in a file with name ".profile" in your home directory.
Do this very carefully and don't close the window until you have saved the
change and opened a test window (which will get the new .profile).

Do not do this if you are `root`.
. What kind of logic errors can changing the control variable inside a for loop
The results are completely unpredictable.  You could do all the wrong
calculations -- or if clever and lucky the right ones.

The loop may very well go on forever....
. Why do non-void functions without a return give a changing number
A function that is not void is supposed to leave the result on top of a stack of values (called the run-time stack).  If there is no return statement nothing is placed there, but the next part of the program doesn't no that and takes what ever garbage that is on the stack as the returned value.
. What is the purpose of a for loop
Counting.
. When to us a for vs a while
Counting --> for.
. Why do we still use while
Some loops are not counting loop.
. What happens if I miss one of the parts of a for loop
It substitutes "do nothing".  Usually the loop runs forever.
. What happens if I forget parts of a loop using while
It does evil things.

. Which operator has the highest priority
In the operators with two operands it is multiplication and division.
. Does pow(x,n) use a for loop
I don't thinks so.
. Why can't I use a local control variable outside its loop
The compiler doesn't permit this for two reasons.  (1) it reduces bugs.
(2) it lets the same identifier be used in many loops.  You can have a
whole series of
.As_is 	for(int i=1; i<10;i++)...
.As_is 	for(int i=10; i<20; i++)....
. If a controlled variable is declared outside a loop can you use it outside
Yes.  Be careful about the last value left in it.
. Can a comma operator be used in any statement
Yes.  But it is most useful in a for or while statement to increment
several variable:
.As_is 		i++, j--, k*=2
for instance.
. Is there any way to do money better than using a double
You could try doing it in a whole number of cents declared as
.As_is 		long int cents;


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