CIS22A - Notes for Week 4, 10/14-10/17

Announcements and Reminders

Topics

Terminology

rand() function and mod practice

Example - write code to simulate rolling two dice.

How to seed the random number generator

Chapter 4

if statements

if ( condition )  statement;

if ( condition )
  statement;

if ( condition )  {
   block of statements
}

if ( condition )  
{
   block of statements
}

expressions

relational operators

> < == >= <= !=

bool type

The boolalpha manipulator

logical operators

&&
and is an alias for &&
||
or is an alias for ||
!
not is an alias for !

Common if statement problems

if ( x > y );
   cout << " x > y ";

if (x = y)
   cout << " x = y ";

if (x <= y)
   cout << " x is less ";
   cout << " than y ";

if ... else

Program 4-8 - Page 168
Program 4-9 - Page 169

Nested if

Program 4-10 - Page 172
Program 4-11 - Page 173

The dangling else

if (condition)  ...
   if (condition)
      ...
else
   ...

sequence of if statements

if ( condition )
   statement or block
if ( condition )
   statement or block
if ( condition )
   statement or block
if ( condition )
   statement or block
...

sequence of if ... else statments

if ( condition )
   statement or block
else if ( condition )
   statement or block
else if ( condition )
   statement or block
else if ( condition )
   statement or block
else
   statement or block

if ... else Review Problems

Assign a letter grade for

     90 - 100% = A
       80 - 89% = B
       70 - 79% = C
       60 - 69% = D
 less than 60% = F

Generate a random int, x,  between 1 and 10.  The int is big if it is greater than 6, otherwise it is small.

Write if and if ... else statements for the following:
  1. if x is big, print "big"
  2. if x is big, print "big", otherwise print "small"
  3. identify x as big even or small even
  4. identify x as big even, small even, big odd, or small odd
  5. identify x as big, small even or small odd
  6. identify x big or small, even or odd, and a multiple of 3 or not.  How may combinations are there?  Should the if ... else's be separate or nested?

Program 4-20 - Page 197-198

The string == operator

The conditional operator

 aka ternary operator

condition expression1 ? expression2 : expression3

If the condition express1 is true, the operator returns expression2 otherwise it returns expression3.

The switch statement

Syntax:

switch (integral expression)
{
case (integral value1):
   statement(s)
case (integral value2):
   statement(s)
case (integral value3):
   statement(s)
default:
}

block and scope

Example:

Assign a letter grade for
     90 - 100% = A
       80 - 89% = B
       70 - 79% = C
       60 - 69% = D
 less than 60% = F

Example:

Write a program to simulate a random playing card and printing the value of a random card, such as
queen of clubs
Videos

if statement

if Statement.....again?

if / else Statement

Read me		 if statement
condition
block
scope

expression

logical value
type bool
true
false

relational operator
>
<
==
>=
<= !=
logical operator
&&
||
!
alias
and
or
not

fall through

else
nested if
three way condition

dangling else