CMPE 13辅导、辅导style comments、讲解C++、辅导C++编程语言

CMPE 13 Winter 18 LAB 02

Due on JAN 25 @11:59pm

High Level Description:

● Build a scanner for a “calculator” like language with support for comments

Lab Description:

● Create a lab02 directory at gitlab

● Write a scanner for C-like expressions

a = 3+4*(123+a != b)

2+3

foo = (33^0x33|123) && a==3 || b<3

● Support C++ style comments // and /* foo /* bar */ */

○ Tokens in the commented region are not reported

○ For each token found, call add_token(char *start, int tok, int len)

● Google test inside lab02/tests/test1.cpp

● Must have a lab02/makefile

● Code inside lab02/src/calculator.cpp and lab02/src/calculator.h

● Commit only the needed files (extra files will result in point loses)

● For the test1.cpp, the add_token should be used for testing the functionality of calculator.

The TAs will provide other add_token code for testing, so make sure to keep the function

in test1.cpp

API

● int calculator(char *text)

○ Inside calculator.cpp, returns the number of tokens found

● Int add_token(char *start, int tok, int len)

○ Inside test1.cpp, used for testing

○ Start is the beginning position of the token (char *)

○ Tok is the token type:

■ 0 (not valid)

■ 1 variable

■ 2 number

■ 3 operator (,),*,-,+,<,==,>=,<=,/,%,^,&&,&,|,||

■ 4 assign =

○ Len is the number of characters for the token

○ variables is a continuous sequence of alphanumeric (alnum) characters

separated by spaces or non alphanumeric characters. The first character must

not be numeric

○ number is also a continuous sequence of alnum characters, but the first

character must be numeric (0-9)

1/17/2019 lab02 - Google Docs

https://docs.google.com/document/d/1dIkPELuGF-4oXqI5X-pZiv9CtUzGKuHQxLM2c0O_xlQ/edit 2/4

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Example execution:

char *tst1 = "a = 3+3 *588 foo";

int tst1_n_tokens = calculator(tst1);

// Calls:

// add_token(a,1,1)

// add_token(=,4,1)

// add_token(3,2,1)

// add_token(+,3,1)

// add_token(3,2,1)

// add_token(*,3,1)

// add_token(588,2,3)

// add_token(foo,1,3)

assert(tst1_n_tokens==8);

1/17/2019 lab02 - Google Docs

https://docs.google.com/document/d/1dIkPELuGF-4oXqI5X-pZiv9CtUzGKuHQxLM2c0O_xlQ/edit 3/4

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High level pseudo-code:

// You can do a different algorithm or structure. This is a hint to better understand the

// expected functionality and to provide a starting point for your program.

// A direct translation of this pseudo-code to C will NOT work. It is a guide, it does

// not cover corner cases. E.g: it does not handle end of file, or it is vague about spaces

// or the “set token based on”

calculator(text)

in_nested_comments = 0

for each character in text

if beginning_comment

In_nested_comment++

call add_token if in_numeric, in_variable

clear In_numeric and in_variable

call add_token if token_next

token_next = 0

else if end of comment

in_nested_comment--

else if in_numeric and character is alnum

still in_numeric

else if in_variable and character is alnum

still in_variable

else if in_two_char_token_option

if valid_second_char

call add_token with new token

else

call add_token with old single_character_token

token_next = set token based on second_character_token

else

call add_token if in_numeric, in_variable

clear In_numeric and in_variable

token_next = set token based on current_character_token

if token_next can be 2 token set in_two_char_token_option

Submission: You will submit the code using gitlab. As mentioned above, Lab is due on JAN 25

@ 11:59PM. We will clone all repos at midnight and will not use git tags. As a result if you wish

to make and fail at a last minute change and push (hence only submitting code changes made

hours/days before), it’s on you

1/17/2019 lab02 - Google Docs

https://docs.google.com/document/d/1dIkPELuGF-4oXqI5X-pZiv9CtUzGKuHQxLM2c0O_xlQ/edit 4/4

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Evaluation/Review: Your repos will be graded by the TAs for:

1) Containing the aforementioned files and directory structure(same file and dir names)

2) Proper working of make, make clean, make test (points will be deducted for any errors,

compilation, runtime, extra files, or other mistakes)

3) Inspection of code (this includes checking for comments, code style and cheating)

4) Test quality (comments, different tokens…)

5) Being able to pass TAs tests (google test)

6) The evaluation rubric and points you get will be posted on canvas