CS 1713/1711 Introduction to Computer Science Lecture 9

CS 1713 Lecture 9: Introduction to Logic and Selection
September 20, 1999

Flow of control
- What is it?
- How do object instantiation and method calls change it?
- What kinds of problems can't be done so far?
Statements done only under certain conditions:
Form: if (condition)
statement_true;
Example: if (myAmIPushed)
System.out.println("I am pushed");
Interpretation: The condition is an expression that has a boolean value (either true or false). The statement_true could be just one or a block of statements closed in curly braces ({}). The statement_true is only done when condition
Statements with two alternatives:
Form: if (condition)
statement_true;
else
statement_false;
Example: if (myAmIPushed)
System.out.println("I am pushed");
Interpretation: The condition is an expression that has a boolean value. The statement could be just one or a block of statements closed in curly braces ({}).
The relational operators:
- Less than: <
- Greater than: >
- Less than or equal to: <
- Greater than or equal to: >
- Equal to: ==
- Not equal to: !=
Note difference between test for equality and the assignment operator (=).
A few examples using simple selection
Work on the Fraction class

Objective: Develop a basic understanding of flow of control.

Last revision: September 17, 1999 at 2:30 pm