1. Increment/Decrement Unary operators require only one operand
++ increment operator
Adds 1 to the value of a variable x ++; is equivalent to x = x + 1;
decrement operator
Subtracts 1 from the value of a variable x --; is equivalent to x = x – 1;
Are the following ok?
(x+y)++
5++

2. V++ vs ++V
int number=2; int value_produced=2*(number++); cout<<value_produced<<endl; cout<<number<<endl; int value_produced=2*(++number);

3. For Loops The next major loop we use is the For Loop
Consider the code below, which is very common
A variable (count) controls the loop – we call it the iteration variable
We initialize it before the loop, we check it to see if we should exit each iteration, and we update its value each iteration
This situation is so common, C++ has a special case of the while loop called the for loop
count = 0;
while (count < 50) {
doSomeStuff();
count++; }

4. For Loops
For loops
Format: for (initialization; condition; update) statements
Does same functionality as while, but more succinctly
Like if and while, for-loops almost always use { } for statement
Frequently used when you know the # of iterations
Example below would normally use a for-loop
count = 0;
while (count < 50) {
doSomeStuff();
count++; }
initialization;
while (condition) {
doSomeStuff();
update; }
for (count=0; count<50;
count++ ) {
doSomeStuff(); }

5. Initialization Action
For Loop Dissection
The for loop uses the same components as the while loop in a more compact form
for (n = 1; n <= 10; n++)
Initialization Action
Boolean Expression
Update Action

6. Which One to Use?
Use "for" loop when number of iterations is known at outset
Use "while" loop if number is unknown or depends on a non-numeric condition

7. Exercises 1.How to calculate 1+2+3+…+100

8. Nested Loop
Example:  The for-j loop is nested (or enclosed within) the control of the for-i loop, so that it is executed ten times.
               for (int i = 0, k = 1; i < 10; i++) {
                                for (int j = 0; j < 10; j++)
k++;
                        }
Final value of k?
Example1: what does the following code do?
for (int i=1; i<=10;i++)
{ for (int j=1; j<=i; j++)
cout<<'*';
cout<<endl; }

9. More examples
for (int n=1; n<=10; n+=2) do something; for (double size=0.75; size<=5; size=size+0.05) for (double x=pow(y,30); x>2.0; x=sqrt(x)) do something