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CS157 HW3: Bishops                

Description                

In the game of chess, the bishop can attack other pieces diagonally.                 

For this assignment, you will write a program called bishops.c. It will read a description of a chessboard (not necessarily eight-by-eight) that contains a number of bishops. The program will tell you which bishops are attacking other bishops.                 

Data File                

Here’s an example of a data file:                 

3x4

. . C .
. . . .
A . . B

The first line is an integer indicating the height of the board, an “x”, and an integer indicating the width of the board. After that follows:

• whitespace, which is ignored
• an “.”, indicating that this square is empty
• an uppercase letter, indicating that a bishop is on that square.

Output                

After reading the data file, the program should indicate which bishops are attacking each other, like this: “A attacks B”.                 

To avoid redundancy, don’t display both “B attacks G” and “G attacks B”. Only display “B attacks G”, since 'B'<'G'.                 

The output lines may be in any order. We will sort your output before looking at it.                 

Sample Runs                

Here are several sample runs, where “% ” is my prompt:                 

% c11 -Wall bishops.c 
% cat bishop-data1
3x4

. . C .
. . . .
A . . B
% ./a.out bishop-data1
A attacks C
% cat bishop-data1-ugly 
3x4
.
.
                C..
    . .  .   A..

  B
% ./a.out bishop-data1-ugly
A attacks C
% cat bishop-data2
8x8

. . . . . . . .
. . . . . . . .
. B . C . . . .
. . . . D . . .
. . . . . E . .
. . . A . . . G
. . . . . . F .
. . . . . . . .
% ./a.out bishop-data2
C attacks D
C attacks E
D attacks E
F attacks G
% cat bishop-data3
3x3

Z G .
. . H
. D Q
% ./a.out bishop-data3
G attacks H
D attacks H
Q attacks Z

    export STACK_FRAME_LINK_OVERRIDE=ffff-ad921d60486366258809553a3db49a4a

Requirements                

• Unlike real chess, the bishops can attack through other pieces.
• You may assume that:
  • Each line in the puzzle file will be at most 80 characters long.
  • the chessboard will be, at most, 50 by 50.
  • The bishops will be unique. For example, there won’t be two bishops called “A”.
• The board does not have to be square.
• If the wrong number of arguments are given, print a message to standard error, including argv[0].
• If the file can’t be opened, print a message to standard error, including argv[0] and the filename.
• If the board can’t be read (first line bad, a '$' is encountered, etc.) then print a message to standard error, including argv[0] and the filename.
• You must have a comment at the very very beginning of the file with your name, date, and purpose of the program.
• If any error message is emitted, stop the program.
• You may not use global variables (global constants, types, and #defines are fine).
  • However, you may have a single global string representing the program name, for error messages.
• Use char constants for char values, not int ASCII values: 'A', not 65.
• Close all files that you open.

How to submit your homework:                

Use web checkin, or:                 

    ~cs157/bin/checkin HW3 bishops.c

How to receive negative points:                

Turn in someone else’s work.                 

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