Programming Assignment #4 Solution

Description




• This is an individual assignment. Please do not collaborate

• If you think that this document does not clearly describes the assignment, ask questions before its too late. This assignment is about implementing and testing classes for a logic circuit simulator.

• Your program reads two files:

– circuit.txt

– input.txt




• According to content in circuit.txt, the program dynamically creates necessary objects for a logic circuit and evaluates the states listed in input.txt.

• Your program prints the output to stdout. Each line in input.txt is a state. For each state, there should be a line of output printed.







circuit.txt




• Each line starts with a keyword. Possible keywords:




INPUT AND

OR NOT FLIPFLOP DECODER




• The first line specifies input labels. Labels are separated by spaces. Example:

INPUT a input2 c3 k




• Here there are 4 inputs are defined. Each has an identifier. a, input2, c3, k.




• The second line specifies output labels. Labels are separated by spaces. Example:

OUTPUT d1 d2 d3 d4




• Here there are 4 outputs are defined. Each has an identifier. d1, d2, d3, d4.

• AND keyword specifies that there is an and gate defined. AND keyword follows the identifier for its output and two other identifiers for the inputs. Example:

AND gate_A c3 another_id




• Here the and gate has an output identified by the string gate_A. Its inputs are identified c3 and another_id.

These identifiers can be input identifiers or identifiers for other gates.

• OR keyword specifies that there is an or gate defined. OR keyword follows the identifier for its output and two other identifiers for the inputs. Example:

OR gate_B ck id3




• Here the or gate has an output identified by the string gate_B. Its inputs are identified ck and id3. These identifiers can be input identifiers or identifiers for other gates.

• NOT keyword specifies that there is a not gate defined. NOT keyword follows the identifier for its output and one other identifier for its input. Example:

NOT gate_C c5




• Here the not gate has an output identified by the string gate_C. It has only one input an it is identified by the string c5.

• FLIPFLOP keyword specifies that there is a flip-flop gate defined. FLIPFLOP keyword follows the identifier for its output and one other identifier for its input. Example:

FLIPFLOP gate_F c6




• Here the flip-flop gate has an output identified by the string gate_F. Its input is identified by c6.

• DECODER keyword specifies that there is a decoder gate defined. DECODER keyword follows the identifiers for its outputs(o1, o2, o3, o4) and identifiers for its inputs(a1, a2). Example:

DECODER d1 d2 d3 d4 g1 another_identifier




• Here the decoder gate has outputs identified by strings o1, o2, o3, o4. Its inputs are identified by g1 and

another_identifier.







input.txt




• Each line is a list of 1 and 0. Example:




1
0
1
1
0
1
1
1
0
0
1
0
1
0
0
1



Example:




• Suppose that circuit.txt is has the following content:

INPUT a b c d

OUTPUT d1 d2 d3 d4

AND and1 a b OR or1 and1 c NOT n1 d FLIPFLOP f1 n1

AND a2 or1 f1

DECODER d1 d2 d3 d4 a2 f1




• input.txt has the following content:




1
1
0
1
1
0
1
0
1
1
1
0
• Assume that initially former-out of any FLIPFLOP is 0.

• Any FLIPFLOPs should preserve the state throughout the evaluation of the whole input.txt.

• Each line in input.txt is assigned to identifiers a, b, c, d, defined in circuit.txt. According to the truth tables, outputs of gates are calculated.




• For the input.txt given, the output of your program should be:




1
0
0
0
0
0
0
1
1
0
0
0
a and

gate and1 or or1







and
gate

b

c

flip flop

gate a2

f1
not

d

gate

n1 d1

d3

decoder d2

d4






Figure 1: Example Logic Circuit







Remarks




• Each identifier is unique. You can assume that their length is limited to 15 characters. You can use

std::string.

• There won’t be any errors in the files.

• You have to use dynamic memory allocation and C++ classes.

• You have use inheritance and polymorphism. Find a class hierarchy and try to use abstraction.

• You are not allowed to used std::vectors.

• You cannot use components which are not covered in class. (such as templates etc..)

• In order to learn about file I/O operations, you can go through the related book chapter(not covered in class).

Or you can read the section presented in assignment 3.







Turn in:




• Source code of a complete C++ program and a suitable makefile. You should use c++11 standard. Your code will be tested in a linux-gcc environment.

• A script will be used in order to check the correctness of your results. So, be careful not to violate the expected output format.

• Provide comments unless you are not interested in partial credit. (If I cannot easily understand your design, you may loose points.)




• You cannot get full credit if your implementation contradicts with the statements in this document.



• FLIPFLOP






a
former_out
out






0
0
0






0
1
1






1
0
1






1
1
0





• DECODER












a1


a2 d1 d2
d3
d4


0


0 0 0
0
1


0


1 0 0
1
0


1


0 0 1
0
0


1


1 1 0
0
0



Truth Tables:




• AND




a


b
out


0


0
0


0


1
0


1


0
0


1


1
1



• OR










a


b
out


0


0
0


0


1
1


1


0
1


1


1
1



• NOT












a


out




0


1




1


0