Exercise 4-2 (Aliasing objects)

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Exercise 4-2     TIJ, p. 66

Exercise 4-2: (1) Create a class containing a float and use it to demonstrate aliasing.

Assignment.java     TIJ, p. 65

import static java.lang.System.out;

class Tank
{
float level;
}

public class Assignment
{
static void println(Object obj) {out.println(obj);}

public static void main(String[] args)
{
Tank t1 = new Tank();
Tank t2 = new Tank();
// t1.level = 9; // int to float OK, no precision loss
t1.level = 9.0f; // 9.0 is implicitly double (compile error)
t2.level = 47.0f;
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
t1.level = t2.level; // not aliasing the fields
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
t1.level = 27.0f;
t2.level = 57.0f;
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
t1 = t2; // aliasing objects
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
t1.level = 27.0f;
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
t2.level = 57.0f;
println("t1.level: " + t1.level + ", t2.level: " + t2.level);
}
}
/*
javac Assignment.java
java Assignment
t1.level: 9.0, t2.level: 47.0
t1.level: 47.0, t2.level: 47.0
t1.level: 27.0, t2.level: 57.0
t1.level: 57.0, t2.level: 57.0
t1.level: 27.0, t2.level: 27.0
t1.level: 57.0, t2.level: 57.0
*/

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