Lab 12

For all problems involving random number generation, add code to ensure that each time the program runs, the random number sequence is distinct.

1. Write a complete C++ program that does the following:
• Prompt the user for a positive integer greater than or equal to 10.
• If the user enters an invalid input, force the user to enter a valid input.
• Print to the monitor a random number between 1 and the user's number.
Sample run of program:

Enter a number greater than or equal to 10: 7 Invalid input! Try again: 11 Random number between 1 and 11 is 9
2. Write a complete C++ program that does the following:
• Prompt the user for two positive integers. The difference in value between the two integers must be at least 10. For example:
• 9 and 15 would be invalid inputs because 15 is only 6 more than 9.
• 14 and 25 would be valid inputs because the difference between the two is 11, which is greater than 10.
• If the user enters an invalid input, tell the user "Invalid input" and force the user to enter valid inputs.
• Print to the monitor a random number between the smaller number entered by the user and the larger number entered by the user.
Sample run of program:

Enter two positive integers with a difference of at least 10: -1 15 Invalid input! Try again: 5 9 Invalid input! Try again: 15 39 Random number between 15 and 39 is 23
3. Write a complete C++ program that simulates rolls of a die.
• The program will prompt the user for a positive integer, which will be the number of die rolls simulated.
• If the user enters an invalid number, tell the user we are not playing games and end the program.
• If the user enters a valid number n, use a loop to simulate to simulate n die rolls.
• For each die roll, print the roll number and the simulated die roll value.
• At the end of the die rolls, the program will print the total count of ones rolled.
Sample run of program:

Enter a number of die rolls: 5 Roll 1: 2 Roll 2: 3 Roll 3: 6 Roll 4: 1 Roll 5: 2 Total number of ones rolled: 1


4. Write a C++ program to play a guessing game:
• The computer randomly generates a number between 1 and 100 inclusive and asks the user to guess the number.
• After each guess, the computer gives a hint:
• If the guess is bigger the program prints "too big".
• If the guess is smaller the program prints "too small".
• The computer then asks the user to guess again.
• The computer keeps track of the number of guesses.
• When the user's guess is correct, it prints "Congratulations! You took n guesses" where n is the number of guesses.
Sample run of program:

Guess the number I'm thinking of between 1 and 100: 50 Too big 40 Too small 45 Too big 43 Too small 44 Congratulations! You took 5 guesses.


5. Write a C++ program to simulate repeated coin tosses with a penny for 10, 100, 1000, and 5000 repeats.
• Simulate each toss by randomly generating a number between 0 and 1 inclusive.
• 0 is tails and 1 is heads.
• Keep a count of the numbers of 0's and 1's generated per set of simulations.
• Divide the resulting counts by the total number of simulations to compute the relative frequency of each possible result.
• See how the probability of getting heads versus probability of getting tails changes with the number of simulations.
• Do these probabilities stabilize as the number of simulations increase?
Sample run of program:

Probability of heads given 10 tosses = 0.6 Probability of tails given 10 tosses = 0.4 Probability of heads given 100 tosses = 0.53 Probability of tails given 100 tosses = 0.47 Probability of heads given 1000 tosses = 0.484 Probability of tails given 1000 tosses = 0.516 Probability of heads given 5000 tosses = 0.4974 Probability of tails given 5000 tosses = 0.5026