1. FOR statement a compact notation for a WHILE e.g. sumgrades = 0;
for (i = 1; i <= 25; i++) {
cin >> grade;
sumgrades = sumgrades + grade; }
syntax:
Initialization Test Update
for ( InitStatement; Expression1; Expression2 )
statement;

2. Sum the first 100 integers WHILE DO WHILE FOR sum = 0; sum = 0;
i = 1; i = 1;
while (i <= 100) do
{ {
sum = sum + i; sum = sum + i;
i++; i++;
} } while(i <= 100);
FOR
sum = 0;
for (i = 1; i <= 100; i++)
sum = sum + i;

3. Nested FOR statement processes in 2 dimensions will print 1 12 123
for (lastnum = 1; lastnum <= 7; lastnum++) {
for (number = 1; number <= lastnum; number++)
cout << number;
cout << endl; }
will print 1 12
123
1234
12345
123456

4. Problem: Print out the integers 5, 10, 15…100 each on a separate line
for (i=5; i<100; i=i+5) {
cout << i << endl; }
i=5;
while (i<=100)
i=i+5;
for (i=1; i<=20; i++) {
cout << 5*i << end; }

5. DOCUMENTATION Each program should contain: 1. Comment Section
PROGRAM: name of program
AUTHOR: your name and SSN
SYSTEM: compiler and operating system
DATE: date
PURPOSE: short description of problem which program “solves”
2. Header Part
#include (all header files)

6. DOCUMENTATION 3. Declaration Part 4. Statement Part
Use realistic names for constants
Use realistic names for variables (and explain their use)
4. Statement Part
Include about 10% comments on subtasks to be performed
Include blank lines for readability
Use indentation (~ 4 spaces)
Include prompts for keyboard input
Line up long “cin” and “cout”
e.g. cout << << <<
<< << << endl;

7. Setting Padding This will produce the output: Padding Output
Eliminated coverage of the functional form… the manipulator is more compact and less complicated syntactically.
Padding Output
- Padding refers to the character used to fill in the unused space in an output field.
- By default the pad character for justified output is the space (blank) character.
- This can be changed by using the setfill() manipulator:
int ID = ;
cout << " " << endl;
cout << setw(10) << ID << endl;
cout << setfill('0'); //pad with zeroes
cout << setfill(' '); //reset padding to spaces
This will produce the output:
413225

8. Scope
The region of program code where it is legal to reference (use) an identifier.
Example
if (alpha > 3) {
int n;
cin >> n;
beta = beta + n; }
The scope of the identifier n
is the body of the if statement.

9. Categories of Scope Local scope Global scope
The scope of an identifier declared inside a block extends from the point of declaration to the end of that block.
Global scope
The scope of an identifier declared outside of all blocks extends from the point of declaration to the end of the entire file.

10. Local Scope (Example) int x; … while (x < 0) { int y;
cin >> y;
x = x + y; }
The scope of y is local to the body
of the while loop.
The scope of x is nonlocal to the body

11. Global Scope (Example)
double d;
int main () {
int y = 0;
cin >> d;
if (d < 0)
d = y; }
return 0;
The identifier d has a global scope.
It can be referenced anywhere in the
program below where it is declared,
including inside main and in the body
of the if statement.
What if a second variable named d was declared in main?

12. Name Precedence
When a block declares a local identifier with the same name as a global identifier, the local identifier takes precedence.
Example
double d = 1.2;
int main() {
double d = 3.5;
cout << d; // 3.5 is printed }

13. Scope Rules Global identifier Local identifier
Declaration to the end of the file.
Local identifier
Declaration to the end of the block.
Does not include any nested block that contains a locally declared identifier with the same name.

14. Scope Examples int a; char c; int main () { while (…) int b; }
return 0;

15. Variables Recall that variables in C++ are made up of four parts Name
Type
Memory location
Value

16. Lifetime
The period of time during program execution when an identifier has memory allocated to it.
A local variable's lifetime
Starts when entering the block
Ends when the block is exited.
A global variable's lifetime
Duration of the entire program.

17. Lifetime Example // c is neither in scope, nor has
// memory allocated to it
while (…)
{ // c is allocated memory
char c; // c is in scope and has memory
} // c's memory is deallocated

18. Lifetime != Scope int a; char c; int main () { while (…) int b; }
return 0;
The lifetime of global identifiers a and c
extends for the duration of the entire program.
However, the global variable a is not in
scope in main. It is hidden by the local
variable a declared in main.
Likewise in the while loop, the global variable
c has memory allocated to it but is not in
scope.