1. AP Java
Review If
else

2. Learning Objectives
Be able to implement Java’s if and if..else into a program.
Be able to evaluate boolean conditions.

3. What do you recall about…
Types in Java
Math operations
Getting information from the user
Showing information on the screen
Byte Code, Java Virtual Machine, Compiling
Class
Method
JavaDocs

4. if sample number1 = input.nextInt(); // read first number from user
// Fig. 2.15: Comparison.java
// Compare integers using if statements, relational operators
// and equality operators.
import java.util.Scanner; // program uses class Scanner
public class Comparison {
// main method begins execution of Java application
public static void main( String args[] )
// create Scanner to obtain input from command window
Scanner input = new Scanner( System.in );
int number1; // first number to compare
int number2; // second number to compare
System.out.print( "Enter first integer: " ); // prompt
number1 = input.nextInt(); // read first number from user
System.out.print( "Enter second integer: " ); // prompt
number2 = input.nextInt(); // read second number from user
if ( number1 == number2 )
System.out.printf( "%d == %d\n", number1, number2 );
if ( number1 != number2 )
System.out.printf( "%d != %d\n", number1, number2 );
if ( number1 < number2 )
System.out.printf( "%d < %d\n", number1, number2 );
if ( number1 > number2 )
System.out.printf( "%d > %d\n", number1, number2 );
if ( number1 <= number2 )
System.out.printf( "%d <= %d\n", number1, number2 );
if ( number1 >= number2 )
System.out.printf( "%d >= %d\n", number1, number2 );
} // end method main
} // end class Comparison
if sample

5. If
If (condition) {
Commands; }

6. Conditions Pascal Java Example = == (x==y) <> != (x!=y) >
>=
(x>=y)
<=
(x<=y)
AND
&&
(x<y)&&(y<z) OR II
(x>y)||(x<z)

7. Order of operations for comparisons()
*, /, % Multiplicative operators
+, - Additive operators
<, >, >=, <= Relational operators
==, != Then do any comparisons for equality and inequality
&& Logical and
|| Logical or
= Assignment operator

8. Is it true or false? boolean test1 = 1 < 2;

9. *, /, % Multiplicative operators +, - Additive operators
Logical Operators Worksheet If x = -2, y = 5, z = 0 , and t = -4, what is the value of each of the following logical expressions?
x + y < z + 1
x - 2 * y + y < z * 2 / 3
3 * y / 4 < 8 && y >= 4
t > 5 || z < 2
x * y < 10 || y * z < 10
(y + 2) / 3 > 3 && t < 0
x * 3 > 0 || y + 5 / t < 2
!(x > 0)
!(x * t < 10) || y / x * 4 < y * 2
t > 5 || z < (y + 5) && y < 3
!(4 + 5 * y >= z - 4) && (z - 2 < 7)
Write syntactically correct logical expressions for the following conditions:
m is less than 100
n is positive and greater than m
m is between 5 and 10 (inclusive)
k is less than 1 or greater than 2
j and k are both negative
i is an even number
Order of Operations ()
*, /, % Multiplicative operators
+, - Additive operators
<, >, >=, <= Relational operators
==, != Then do any comparisons for equality and inequality
&& Logical and
|| Logical or
= Assignment operator

10. You can leave off the {} if there is only one command line.
If else
You can leave off the {} if there is only one command line.
if (condition) {
commands; }
else
Commands;

11. System.out.println("Young 'en"); else if (age<20)
import java.util.Scanner;
//Smith's if..else sample
public class IfElseSample {
public static void main(String[] args) {
int age=0;
//create Scanner to obtain input from command window
Scanner input = new Scanner( System.in );
System.out.println("Please enter your age");
age = input.nextInt();
if (age<=12)
System.out.println("Young 'en");
else if (age<20)
System.out.println("Teeny bopper");
else if (age < 65)
System.out.println("Time for work");
System.out.println("prep for retirement"); }
else
System.out.println("Retire");
System.out.println("second career");
System.out.println("Pay off kids college");

12. Programs: Complete the following.
Modify the quadratic equation program to also calculate imaginary roots.
If b2 – 4ac >= 0 then display the real roots
Else show the imaginary roots
Input three real numbers, and print the numbers in sorted order.
Write a program that inputs a persons name, rate of pay, and the number of hours worked during the week. The program will calculate the pay for the person. For every hour of overtime work (over 40 hours in the week) the person gets paid 150 percent of the regular wage.
Example: Input: Sue, $10.00 per hour rate, 45 hours
Calculation: pay = 10* *10*5 = $475
Input a value representing a person’s percent score (example inputting 80 represents an 80% score), write a program that will output the corresponding letter grade. ‘A’ for , ‘B’ for 80 to 89, etc.