Main Contents Page
CTEC1401 Programming in C
 Quick Reference
Week 8: Iteration
Week 9: Arrays
 Week 10: Pointers I

  1. Before the lab session read CFTTP Chapter 7 and study the solved exercises very carefully.

  2. init1

    Write a C program init1.c that

    1. defines an int array of size ten;
    2. and, using a for loop, initialises each element to zero (i.e. arrayk ∈ {0..9} = 0);
    3. uses another for loop to print out the ten array elements.

  3. init2

    Write a C program init2.c that

    1. defines an int array of size ten;
    2. and, using a for loop, initialises each element to the same value as its index (i.e. arrayk ∈ {0..9} = k);
    3. uses another for loop to print out the ten array elements.

  4. init3

    Write a C program init3.c that

    1. defines an int array of size ten;
    2. and, using a for loop, initialises each element to zero if its index is even and one if its index is odd;
    3. uses another for loop to print out the ten array elements.

  5. reverse1

    Write a C program reverse1.c that prompts the user and, using a for loop, reads in ten int numbers and then, using another for loop, prints them out in reverse order. You should use an array to store the ten numbers.

  6. reverse2

    Write a C program reverse2.c that prompts the user and, using a for loop, reads in twenty int numbers and then, using another for loop, prints out the elements at even indexes in reverse order starting at index 18 and finishing at index 2 (inclusive).

  7. lottery1

    Suppose that the following declaration defines the number of times that each of the national lottery balls (1 ..49) has been drawn over a given period. 

    int lottery[49] = { 23,16,18,19,26,13,22,    /*  1 ..  7 */
                    20,14,22,18,21,15,17,    /*  8 .. 14 */
                    24,15,18,20,13,14,20,    /* 15 .. 21 */
                    18,22,20,16,19,11,20,    /* 22 .. 28 */
                    16,28,22,20,15,17,17,    /* 29 .. 35 */
                    21,21,19,20,14,22,25,    /* 36 .. 42 */
                    19,17,26,18,20,23,12 };  /* 43 .. 49 */
    Write a program lottery1.c to print a histogram showing the information graphically using stars like this: 
     1 (23)  | ***********************
 2 (16)  | ****************
 3 (18)  | ******************
 4 (19)  | *******************
 5 (26)  | **************************
 6 (13)  | *************
 7 (22)  | **********************
 8 (20)  | ********************
 9 (14)  | **************
10 (22)  | **********************
11 (18)  | ******************
12 (21)  | *********************
13 (15)  | ***************
14 (17)  | *****************
15 (24)  | ************************
16 (15)  | ***************
17 (18)  | ******************
18 (20)  | ********************
19 (13)  | *************
20 (14)  | **************
21 (20)  | ********************
22 (18)  | ******************
23 (22)  | **********************
24 (20)  | ********************
25 (16)  | ****************
26 (19)  | *******************
27 (11)  | ***********
28 (20)  | ********************
29 (16)  | ****************
30 (28)  | ****************************
31 (22)  | **********************
32 (20)  | ********************
33 (15)  | ***************
34 (17)  | *****************
35 (17)  | *****************
36 (21)  | *********************
37 (21)  | *********************
38 (19)  | *******************
39 (20)  | ********************
40 (14)  | **************
41 (22)  | **********************
42 (25)  | *************************
43 (19)  | *******************
44 (17)  | *****************
45 (26)  | **************************
46 (18)  | ******************
47 (20)  | ********************
48 (23)  | ***********************
49 (12)  | ************

    8. Supplementary Exercises

  8. lottery2

    Rewrite your lottery1 program as lottery2.c. However, the output should display the "bars" using blocks enclosed by '_' (unerscores) and '| (vertical bars) as show below. (Note, this is slightly tricky): 

              _______________________
 1 (23)  |_______________________|
 2 (16)  |________________|_
 3 (18)  |__________________|
 4 (19)  |___________________|______
 5 (26)  |__________________________|
 6 (13)  |_____________|________
 7 (22)  |______________________|
 8 (20)  |____________________|
 9 (14)  |______________|_______
10 (22)  |______________________|
11 (18)  |__________________|__
12 (21)  |_____________________|
13 (15)  |_______________|_
14 (17)  |_________________|______
15 (24)  |________________________|
16 (15)  |_______________|__
17 (18)  |__________________|_
18 (20)  |____________________|
19 (13)  |_____________|
20 (14)  |______________|_____
21 (20)  |____________________|
22 (18)  |__________________|___
23 (22)  |______________________|
24 (20)  |____________________|
25 (16)  |________________|__
26 (19)  |___________________|
27 (11)  |___________|________
28 (20)  |____________________|
29 (16)  |________________|___________
30 (28)  |____________________________|
31 (22)  |______________________|
32 (20)  |____________________|
33 (15)  |_______________|_
34 (17)  |_________________|
35 (17)  |_________________|___
36 (21)  |_____________________|
37 (21)  |_____________________|
38 (19)  |___________________|
39 (20)  |____________________|
40 (14)  |______________|_______
41 (22)  |______________________|__
42 (25)  |_________________________|
43 (19)  |___________________|
44 (17)  |_________________|________
45 (26)  |__________________________|
46 (18)  |__________________|_
47 (20)  |____________________|__
48 (23)  |_______________________|
48 (12)  |____________|

  9. fibonacci

    The famous Fibonacci number sequence starts like this:

    1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377,...

    Each number in the sequence is the sum of the previous two.

    Write a C program fibonacci.c that

    1. declares an integer array of size 40called fibs which will be used to store the first forty Fibonacci numbers.
    2. assigns the value 1 to each of the first two elements of the array;
    3. uses a for loop to assign the correct values to the rest of the array.
    4. When you have populated the array print it out.

    How far can you extend this sequence until the values are too big to be stored using an int variable?

  10. monthlysales

    Create a text file called monthlysales.c that contains the following C program:

    #include <stdio.h>

main()
{
    int sales[12] = {100,90,120,150,160,170,170,120,140,100,100,90};
    int count;
    printf("Jan\tFeb\tMar\tApr\tMay\tJun\tJul\tAug\tSep\tOct\tNov\tDec\n");
    for(count=0;count<12;count++)
    {
        printf("%d\t",sales[count]);
    }
    printf("\n");
}
    1. Save the file and then compile and run the program.
    2. Modify monthlysales.c so that instead it prints the sales for each quarter i.e. the totals for Jan - Mar, Apr - Jun, Jul - Sep, and Oct - Dec in the form 
           Quarter 1: ????
     Quarter 2: ????
     Quarter 3: ????
     Quarter 4: ????