SI 204 Spring 2017 / HWs


Homework 25: 2D arrays and sorting practice

Name: _____________________________________________ Alpha: ___________________

Describe help received: ________________________________________________________

  • Due before class on Friday, March 24
  • This homework contains code to be submitted electronically. Put your code in a folder called hw25 and submit using the 204sub command.
  • This is a written homework - be sure to turn in a hard-copy of your completed assignment before the deadline. Use the codeprint command to print out your code and turn that in as well.

Assignment

  1. Circle one to indicate how you did for the reading assignment from Homework 23 before class on Monday:

    How carefully did you complete the reading? (Circle one)

    Not at all
    Skimmed it
    Read some
    Read all
  2. Circle one to indicate how you did for the reading assignment from Homework 24 before class on Wednesday:

    How carefully did you complete the reading? (Circle one)

    Not at all
    Skimmed it
    Read some
    Read all
  3. Given the following definitions:
    double x;
    char* s;
    double* A;
    int** M;
    char** W;
    fill in the following table with the type (only) of each expression. Write ERROR for both if the expression would be a compiler or run-time error.
    expressiontype (or ERROR)
    x
    s
    A
    M
    W
    x[0]
    s[0]
    A[0]
    M[0]
    W[0]
    x[0][0]
    s[0][0]
    A[0][0]
    M[0][0]
    W[0][0]
  4. Write the code that would define (that means, declare, allocate, and initialize) the 2D array of `double`s shown in the following diagram:
  5. Download the program hw25.c as well as the file letters.txt that it uses. Compile and run the program to understand what it does.

    Note that this program uses the fgetc function from stdin.h, which reads in a single character (including whitespace) from an open file.

    Your task is just to simplify this program! Make some functions, avoid repeated code, and combine things so that the program is well-structured, easy to understand, and easy to maintain or modify. Submit your updated version as hw25.txt.

  6. Write a program oddfirst.c that reads 10 positive ints from the user and prints them into order so that all the odd numbers come first (in increasing size) followed by all the even numbers (in increasing size).

    There is a "good" way to do this, and (many) "ugly" ways to do it. Do it the good way!

    For example:

    roche@ubuntu$ ./oddfirst
    18 2 7 14 29 3 5 8 16 11
    3 5 7 11 29 2 8 14 16 18