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Unformatted text preview: cs of if  else
if (condition) { statement1; } else { statement2; } statement3; • statement1 happens
if condition is true
• statement2 happens
if condition is false
• statement1 and
statement2 will both
never execute
• statement3 is always
executed afterwards
10 Skipping else if (condition) { statement1; } statement3; Start Evaluate
condition true false Run
statement1 Run
statement3 11 Code blocks
• Code can be grouped into blocks
– All lines of code (statements) are executed
(sequentially) together
– Syntax: { statement1; statement2; statement3; … } 12 Introduction to Boolean Expressions
• The value of a boolean expression is either
true or false
• Examples
num > 0
num < 20
balance <= 0
time < limit 13 Comparison operators
Math
English
notation
= ≠ > ≥ < ≤ Java
Java example
notation Equal to
Not equal to
Greater than
Greater than or equal to
Less than
Less than or equal to == != > >= < <= grade == 95 answer != 42 input > 0 notNegative >= 0 change < DOLLAR negative <=  1 Taken from page 145 of the textbook
14 Math is not Java
• Comparison operators
– Binary operators
– Work from left to right
– How does this evaluate? 0 < score <= 100 15 Math is not Java
If score is 95… 0 < score <= 100 true <= 100 Does not compute?! 16 Solution
Logical operators combine 2 boolean ex...
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This note was uploaded on 02/17/2014 for the course ITP 109 taught by Professor Trinagregory during the Spring '12 term at USC.
 Spring '12
 TrinaGregory

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