Assignment 3: Decoder

Write a program that converts a sequence of bits into messages (this process is known as decoding). There are four types of bit encoding: 0, 10, 110, 111. The corresponding message for each bit encoding is shown below.

• 0 -> Fine

• 10 -> Cloudy

• 110 -> Rainy

• 111 -> Snow

Example 1 (click to see the figure):

Enter a sequence of bits: 110010111

Rainy Fine Cloudy Snow

• Your solution should be based on the code template.

• You can assume that all the input sequences are legal.

• Your program must conform the following requirements:

  • The outputs of your program should behave as in Example 1.

    • program input: 110010111

    • program output: Rainy Fine Cloudy Snow

  • Each message (Fine, Rainy, Cloudy, Snow) is case sensitive and is separated by one space.

  • Do not output any \n or endl.

  • Do not modify the cout statements in the code template.

  • Use cin >> code;

    • Do not use getline(cin, code); otherwise your assignment will not be processed.

    • This is due to the limitation of the evaluating program.

• More input-output samples.

• If you are interested in the story behind this assignment, you can read Demystify Entropy.

• To check whether an input bit is 0, you can use code[i] == '0'

• Suggestions

  • When you wan to access code[i], you can add the following to two assertions before your statement to ensure that index i is within the valid range.

   assert(i >= 0);

   assert(i < code.length());

   cout << code[i] << endl;

• • Similarly, if you want to access code[i+1], you can add the following two assertions before your statement to ensure that index i+1 is within the valid range.

   assert(i+1 >= 0);

   assert(i+1 < code.length());

   cout << code[i+1] << endl;

• • If the array index is not within the valid range, your program will cause runtime error or unknown results.

  • The accuracy of your program is ZERO if any runtime error occurs.