COMP1721 - Higher Computing 1B

1. What would be the result of compiling and executing this C?

           int x = 1, y = 10;
           
           while (x < y) {
               printf("%d\n", x*y);
               x = x + 1;
               y = y - 1;
           }
   

2. Write a C program which reads an integer n and prints the sum of the series:

   1 + 1/2 + 1/3 + .... + 1/n
   

   For example:

   % a.out
   Enter n: 2
   1.5
   % a.out
   Enter n: 10
   2.9289682539682538
   

3. Write a C program computes an estimate of pi using this series:

   4 - 4/3 + 4/5 - 4/7 + 4/9 - 4/11 + .....
   

   You must invent a suitable stopping condition.

4. This question involves simulating the rolling a pair of six-sided dice in C.

   Recall from lectures that the function rand() yields a pseudom-random int.

   First, write a C program which simulates rolling the pair of dice once. The output from your program should look like this:

   % a.out
   You rolled 1 and 2 = 3
   % a.out
   You rolled 5 and 5 = 10
   % a.out
   You rolled 6 and 2 = 8
   

   Second, modify the program to ask the user how many times to roll the dice. The output from your program should look like this:

   % a.out
   How many times should I roll the dice? 5
   You rolled 5 and 1 = 6
   You rolled 1 and 5 = 6
   You rolled 6 and 1 = 7
   You rolled 4 and 3 = 7
   You rolled 4 and 2 = 6
   

   Third, modify the program to also output a tally of the number of sevens rolled. The output from your program should look like this:

   %  a.out
   How many times should I roll the dice? 5
   You rolled 2 and 2 = 4
   You rolled 3 and 1 = 4
   You rolled 2 and 5 = 7
   You rolled 6 and 4 = 10
   You rolled 2 and 5 = 7
   2 7s were rolled
   

5. This question involves simulating the rolling a pair of six-sided dice in C.

   Recall from lectures that the function rand() yields a pseudom-random int.

   Write a C program which asks the user how many times to roll a pair of 6 sided dice and prints a tally of all the numbers rolled. Don't output zero tallies. The output from your program should look like this:

   % a.out
   How many times should I roll the dice? 8
   You rolled 4 and 6 = 10
   You rolled 1 and 2 = 3
   You rolled 4 and 6 = 10
   You rolled 6 and 5 = 11
   You rolled 3 and 6 = 9
   You rolled 1 and 2 = 3
   You rolled 5 and 4 = 9
   You rolled 3 and 6 = 9
   2 3s were rolled
   3 9s were rolled
   2 10s were rolled
   1 11s were rolled
   

   Use an array to store the tallies.