# teaching machines

## CS 145 Lecture 3 – Variables, Types, and Named Operations

September 8, 2014 by . Filed under cs145, fall 2014, lectures.

### Agenda

• what ?s
• program this
• concatenation
• variables
• types
• declarations
• declassignments
• printf
• named operations in the Math class

### TODO

• Start homework 1. Due before September 19.

### Program This

• How can one determine the position of a ball launched into the air? What does one need to know?

### Code

#### Projectile.java

package lecture0908;

public class Projectile {
public static void main(String[] args) {
double t = 5;
System.out.printf("(%f,%f),",
632 * t + 0.0,
20.0 + 1 * t - 4.9 * t * t);

t = 10;
System.out.printf("(%f,%f),",
632 * t + 0.0,
20.0 + 1 * t - 4.9 * t * t);

t = 0.1;
System.out.printf("(%f,%f)",
632 * t + 0.0,
20.0 + 1 * t - 4.9 * t * t);
}
}

#### NamedOperations.java

package lecture0908;

public class NamedOperations {
public static void main(String[] args) {
System.out.println(Math.pow(26, 4));

double score1 = 78.1;
double score2 = 85.5;
double worse = Math.min(score1, score2);
double rounded = Math.floor(worse);
System.out.println(rounded);
System.out.println(Math.floor(Math.min(score1, score2)));
}
}

### Haiku

on the power of naming things:
Say “F U, Cancer!”
You can ‘cuz it has a name