Lab 6A: Coin Tosses

Background:

We can generate random numbers in C++ using the rand() function (declared in the cstdlib header file). rand() returns a random integer between 0 and RAND_MAX (which is also defined in the cstdlib header file). C++ does not automatically seed the random number generator. We can do that with: srand();. srand() should be called once once in a program and it takes an unsigned int as it's only argument. To produce different result each time your program is run, use: srand( time(NULL) );. The time() function is declared in the time.h header file.

Assignment:

Design an algorithm that simulates a coin being tossed and counts (and displays) how many coin tosses it takes to get 4 heads in a row. Implement your algorithm in a new project (within your existing CodeLite workspace). Verify that different runs yields different results.

Examples

The following are examples of correct execution. Because the result of the coin tosses are randomly generated, your program will probably not match the exact sequence of tosses.

Heads
Heads
Heads
Tails
Heads
Heads
Tails
Heads
Heads
Heads
Heads
It took 11 tosses this time to get 4 heads in a row.

Heads
Tails
Heads
Heads
Tails
Tails
Tails
Tails
Heads
Tails
Heads
Tails
Tails
Heads
Heads
Heads
Heads
It took 17 tosses this time to get 4 heads in a row.

Submission

Submit your source code using the handin program. For handin, for this lab, type the following in a terminal window exactly as it appears:

handin  lab6A  main.cpp

To verify your submission, type the following in a terminal window:

handin  lab6A

Rubric:

Points  Item
------  --------------------------------------------------------------
10      Documentation
        Header comment block at the beginning of each file with:
        + Your full name
        + Date(s) code was written
        + Description
        Comments explaining the role of each variable and major section of code

40      Correctness
        Program solves the assigned problem using methods described in program description
        Program compiles without errors
        Program executes without crashing
        Program produces the correct output
------  --------------------------------------------------------------
50      Total

Notes:

To make you program produce the same result every time, which will aid in debugging, use the following call to seed the random number generator (before any calls to rand()):

srand( time(0) );

Note, be sure to set it back to srand( time(NULL) ); before submitting your assignment.

CSCI 2170