Using the Coin Class The Coin class from Listing 5.4 in the text is in the file Coin.java. Copy it to your directory, then write a program to find the length of the longest run of heads in 100 flips of the coin. A skeleton of the program is in the file Runs.java. To use the Coin class you need to do the following in the program: 1. Create a coin object. 2. Inside the loop, you should use the flip method to flip the coin, the toString method (used implicitly) to print the results of the flip, and the getFace method to see if the result was HEADS. Keeping track of the current run length (the number of times in a row that the coin was HEADS) and the maximum run length is an exercise in loop techniques! 3. Print the result after the loop. // ******************************************************************* // Coin.java Author: Lewis and Loftus // // Represents a coin with two sides that can be flipped. // ******************************************************************* public class Coin { public final int HEADS = 0; public final int TAILS = 1; private int face; // --------------------------------------------- // Sets up the coin by flipping it initially. // ---------------- ----------------------------- public Coin () { flip(); } // ----------------------------------------------- // Flips the coin by randomly choosing a face. // -------- --------------------------------------- public void flip() { face = (int) (Math.random() * 2); } // ----------------------------------------------------- // Returns the current face of the coin as an integer. // ----------------------------------------------------- public int getFace() { return face; } // ---------------------------------------------------- // Returns the current face of the coin as a string. // ---------------------------------------------------- public String toString() { String faceName; if (face == HEADS) faceName = \"Heads\"; Chapter 5: Conditionals and Loops 87 else faceName = \"Tails\"; return faceName; } } // ******************************************************************** // Runs.java // // Finds the length of the longest run of heads in 100 flips of a coin. // ******************************************************************** import java.util.Scanner; public class Runs { public static void main (String[] args) { final int FLIPS = 100; // number of coin flips int currentRun = 0; // length of the current run of HEADS int maxRun = 0; // length of the maximum run so far Scanner scan = new Scanner(System.in); // Create a coin object // Flip the coin FLIPS times for (int i = 0; i < FLIPS; i++) { // Flip the coin & print the result // Update the run information } // Print the results } } Solution // ******************************************************************* // Coin.java // Represents a coin with two sides that can be flipped. // ******************************************************************* public class Coin { public final int HEADS = 0; public final int TAILS = 1; pri.

1. Using the Coin Class
The Coin class from Listing 5.4 in the text is in the file Coin.java. Copy it to your directory, then
write a program to find the length of the longest run of heads in 100 flips of the coin. A skeleton
of the program is in the file Runs.java. To use the Coin class you need to do the following in the
program:
1. Create a coin object. 2. Inside the loop, you should use the flip method to flip the coin, the
toString method (used implicitly) to print the results of the flip, and the getFace method to see if
the result was HEADS. Keeping track of the current run length (the number of times in a row
that the coin was HEADS) and the maximum run length is an exercise in loop techniques! 3.
Print the result after the loop.
// ******************************************************************* //
Coin.java Author: Lewis and Loftus // // Represents a coin with two sides that can be flipped. //
*******************************************************************
public class Coin { public final int HEADS = 0; public final int TAILS = 1;
private int face;
// --------------------------------------------- // Sets up the coin by flipping it initially. // ----------------
----------------------------- public Coin () { flip(); }
// ----------------------------------------------- // Flips the coin by randomly choosing a face. // --------
--------------------------------------- public void flip() { face = (int) (Math.random() * 2); }
// ----------------------------------------------------- // Returns the current face of the coin as an
integer. // ----------------------------------------------------- public int getFace() { return face; }
// ---------------------------------------------------- // Returns the current face of the coin as a string. //
---------------------------------------------------- public String toString() { String faceName;
if (face == HEADS) faceName = "Heads";
Chapter 5: Conditionals and Loops 87
else faceName = "Tails";
return faceName; } }
// ******************************************************************** //
Runs.java // // Finds the length of the longest run of heads in 100 flips of a coin. //
********************************************************************
import java.util.Scanner;
public class Runs { public static void main (String[] args) { final int FLIPS = 100; // number of
coin flips
int currentRun = 0; // length of the current run of HEADS int maxRun = 0; // length of the
maximum run so far

2. Scanner scan = new Scanner(System.in);
// Create a coin object
// Flip the coin FLIPS times for (int i = 0; i < FLIPS; i++) { // Flip the coin & print the result
// Update the run information
}
// Print the results
} }
Solution
// *******************************************************************
// Coin.java
// Represents a coin with two sides that can be flipped.
// *******************************************************************
public class Coin
{
public final int HEADS = 0;
public final int TAILS = 1;
private int face;
// ---------------------------------------------
// Sets up the coin by flipping it initially.
// ---------------------------------------------
public Coin () { flip(); }
// -----------------------------------------------
// Flips the coin by randomly choosing a face.
// -----------------------------------------------
public void flip() { face = (int) (Math.random() * 2); }
// -----------------------------------------------------
// Returns the current face of the coin as an integer.
// -----------------------------------------------------
public int getFace() { return face; }
// ----------------------------------------------------
// Returns the current face of the coin as a string.
// ----------------------------------------------------
public String toString()

3. {
String faceName;
if (face == HEADS)
faceName = "Heads";
else
faceName = "Tails";
return faceName;
}
}
// ********************************************************************
// Runs.java
// Finds the length of the longest run of heads in 100 flips of a coin.
// ********************************************************************
import java.util.Scanner;
public class Runs
{
public static void main (String[] args)
{
final int FLIPS = 100; // number of coin flips
int currentRun = 0; // length of the current run of HEADS
int maxRun = 0; // length of the maximum run so far
Scanner scan = new Scanner(System.in);
// Create a coin object
Coin c = new Coin();
int face;
// Flip the coin FLIPS times
for (int i = 0; i < FLIPS; i++)
{
// Flip the coin & print the result
c.flip();
face = c.getFace();
System.out.println("Flip " + (i+1) +": " + c.toString());
if(face == 0)

4. currentRun++;
else
{
// Update the run information
if(currentRun > maxRun)
maxRun = currentRun;
currentRun = 0;
}
}
// Print the results
System.out.println("Maximum run of heads in a row: " + maxRun);
}
}
/*
OUTPUT:
Flip 1: Heads
Flip 2: Heads
Flip 3: Heads
Flip 4: Heads
Flip 5: Tails
Flip 6: Heads
Flip 7: Tails
Flip 8: Heads
Flip 9: Heads
Flip 10: Heads
Flip 11: Tails
Flip 12: Tails
Flip 13: Heads
Flip 14: Tails
Flip 15: Heads
Flip 16: Heads

5. Flip 17: Tails
Flip 18: Tails
Flip 19: Heads
Flip 20: Heads
Flip 21: Heads
Flip 22: Tails
Flip 23: Tails
Flip 24: Heads
Flip 25: Tails
Flip 26: Tails
Flip 27: Heads
Flip 28: Tails
Flip 29: Tails
Flip 30: Tails
Flip 31: Heads
Flip 32: Tails
Flip 33: Tails
Flip 34: Heads
Flip 35: Tails
Flip 36: Heads
Flip 37: Heads
Flip 38: Heads
Flip 39: Tails
Flip 40: Heads
Flip 41: Tails
Flip 42: Heads
Flip 43: Tails
Flip 44: Tails
Flip 45: Heads
Flip 46: Tails
Flip 47: Heads
Flip 48: Heads
Flip 49: Heads
Flip 50: Tails
Flip 51: Tails
Flip 52: Heads

6. Flip 53: Heads
Flip 54: Heads
Flip 55: Tails
Flip 56: Heads
Flip 57: Tails
Flip 58: Heads
Flip 59: Heads
Flip 60: Heads
Flip 61: Heads
Flip 62: Heads
Flip 63: Tails
Flip 64: Heads
Flip 65: Heads
Flip 66: Tails
Flip 67: Heads
Flip 68: Tails
Flip 69: Heads
Flip 70: Heads
Flip 71: Tails
Flip 72: Heads
Flip 73: Heads
Flip 74: Heads
Flip 75: Tails
Flip 76: Tails
Flip 77: Tails
Flip 78: Heads
Flip 79: Heads
Flip 80: Heads
Flip 81: Tails
Flip 82: Heads
Flip 83: Heads
Flip 84: Tails
Flip 85: Heads
Flip 86: Heads
Flip 87: Heads
Flip 88: Heads

7. Flip 89: Heads
Flip 90: Tails
Flip 91: Heads
Flip 92: Tails
Flip 93: Tails
Flip 94: Heads
Flip 95: Tails
Flip 96: Tails
Flip 97: Heads
Flip 98: Tails
Flip 99: Tails
Flip 100: Heads
Maximum run of heads in a row: 5
*/