cs Sept 16, 2014

const : some values may not be known at run time cant change the value after being given initial values.
void use (int n)
{
  const int c2 = n + 7; // cant change after being set but can be set during run time
}

constexpr" all the vales are known at compile time and cant change during runtime.
constexpr double pi = 3.14;

Both static memory allocation.

Chapter 4:

Review
5.  compare and contrast expression and statement..
A statement is an expression followed by a semicolon..
4. An expression evaluates something or computation..
2. inputs to an computation cout << x . in this case cout and x.
ouputs of computation: cout<<x is cout object...

Final exam : What is the declaration of this function : cout <<x; or operator<<(cout, x);

ostream  &  operator<<(ostream &, int);

might ask the definition of this function as well.

^. lvalue

a + b

a = b //  a must be a lvalue..

lvalue (variable) are modifed. rvalue are the not modified values..

How many ways an lvalue can be modified ?

1.assignment and cin >> x (input value)
2.assignment statement
3.for (auto x: a)

x changes to each element ..

a is a collection vector array.

How do you avoid unnamed constant.. use symbolic constant.. constexpr double pi = 3.14;
18. cout << ch;
print numeric value of a character..
cout <<(int) ch;

cout<<static_cest<int> (ch);

19. char foo(int x); //declaration of function takes an integer and returns a char..

20. 1. modular, readable.repeatable