Guidelines: The following exercises are to evaluate students’ understanding in the following topics (as essential programming concepts):

  • Basic I/O functions (5%)
  • Selection structure (20%)
  • Repetition structure (20%)
  • Arrays and strings (20%)
  • Functions (10%)
  • Programming techniques (25%)

Each question does not require external libraries or any special knowledge except for basic I/O functions. Skillful students should complete both question within only 20 minutes, while some students may take up to an hour.

Q1. Write a program that takes a string as an input, passes the string to a function which swaps the first 2 vowels of the string, and then prints the result as the output. The input string is assumed to consist only of lower-case letters and have its length of less than 32 characters. The program, however, must meet the following specifications:

  1. The function takes a string as an argument and does not return any value.
  2. The function swaps only the first 2 vowels of the string if 2 or more presented; the string remains unchanged otherwise.
  3. The function should not print any message.
  4. The input and the output must be taken and printed only in the main program.

The followings are expected outputs:

Test case #1

Enter a string:  demo
Output:  dome

Test case #2

Enter a string:  print
Output:  print

Q2. Write a program that takes a string as an input, passes the string to a function which returns the character that most frequently appears in the string, and then prints that character as the output. The input string is assumed to consist only of lower-case letters and have its length of less than 32 characters. The program, however, must meet the following specifications:

  1. The function takes a string as an argument and returns a character.
  2. The function may return any of the characters if many appear equally but most frequently.
  3. The function should not print any message.
  4. The input and the output must be taken and printed only in the main program.

 

The followings are expected outputs:

Test case #1

Enter a string:  macbook
'o' appears most frequently in "macbooK"

Test case #2

Enter a string:  iphone
'e' appears most frequently in "iphone"