Description
Primary Learning Objectives
• Write C programs using arrays and strings.
Requirements
Create a program that will count the occurrences of letters in a user-input string and create a
report.
Your program should begin by asking the user to enter text for analysis. The user should be
able to type up to 1023 characters and hit enter, and your program should be able to store
these characters as a C string. Your program should have a buffer (i.e. char array) for storing
this string that can handle up to the maximum length needed to hold the this amount of
characters (but not more than the amount of space required either).
Your program should then analyze the string to count the number of characters of each letter
from ‘A’ to ‘Z’ in the string. Your program should count both uppercase and lowercase
instances of the characters as an occurrence of the character. In other words, the string
“AaaAbB” would have a count of 4 ‘A’ characters and 2 ‘B’ characters. Your program should
keep track of the count of each A to Z character using an array, not with individual variables.
Your program should output the total occurrences of each character in a table, along with the
percentage of the string that is made up of each character from A-Z. The table should have
three columns:
• Letter – 10 characters, left-aligned
• Occurrences – 15 characters, left-aligned
• Percentage – 15 characters, left-aligned, output two decimal digits of precision
Beneath the table, your program should also output the most frequently occurring character
from A-Z, and the least frequently occurring character from A-Z. If two or more characters are
“tied” for either most frequently occurring character or least frequently occurring character,
then you can output any of those characters as being the most frequently or least frequently
occurring character.
Hint: Remember that characters in C are really just an int number. It’s possible to write a very
simple and short version of this program if you keep this in mind: http://www.asciitable.com/.
Your program should run either identically or near identically to this example, in particular the
occurrences and percentages should be identical:
Here is another example of the program running:
Note that it is OK that the percentages of the A-Z characters in the string do not add up to
100%, we would not expect this because it’s a percentage of the string that is made up of each
character (and the string may includes characters that are not letters from A-Z, so things like
space characters, periods, etc.).
Add some comments to your code that explain what each section of code is responsible for
doing, and if needed because it may not be obvious to the read, explain how the code itself is
carrying out the work it is responsible for doing.
Help
Keep in mind that we’ve written a lot of code in-class and in-lab that is similar to what you need
to implement! We went over an example of user input of a string with spaces in-class, and
finding a minimum number in an array. In-lab during week 4 you will go over examples of
analyzing individual characters in a string (postal code), and finding a maximum number in an
array. We have gone over examples of printing a formatted table too. So much of what you
need to do in this assignment is very similar to these examples, and you should use them to
help you out!
Submission
Save your solution in a file named lettercounter.c and put it in a zip file named as3.zip and
submit them to the Assignment #3 dropbox on Avenue to Learn.
Marking scheme
Component Description Marks
String input String input from the user with a correctly sized buffer. 15
Occurrence
counting
Counting of occurrences done with an array. 30
Percentage
calculation
Calculation of percentages for each character. 10
Most and least
frequent chars
Identification and reporting of the most and least frequent
characters A-Z to occur in the string.
25
Table Output of formatted table 10
Comments Sensible comments documenting the code. 10
Total: 100
