Match Assignment for u0000000 Solution

The goal of this assignment is to give you some practice with C on a problem that is algorithmically straightforward but difficult to get right on a first try. With any luck, you'll have a bug along the way, and then you get to practice using GDB.

Your task is to implement a program that takes command-line arguments and checks whether each argument matches a particular pattern. The pattern to check is determined by a command-line flag: -a, -b, or -c, where the default mode is -a. The patterns for each flag are described below.

By default, your program should print “yes” (always lowercase, no extra space) for each matching argument and “no” (always lowercase, no extra space) for each non-matching argument, each on a separate line. If the -t flag is provided, then your program should instead print nothing for non-matching argument and it should print a converted value for each matching argument. Each pattern mode has an associated conversion, as described below.

At most one of -a, -b, or -c will be provided. A -t flag can be provided before or after any of -a, -b, and -c. All flags (i.e,. up to two of them) precede other command-line arguments. A non-flag argument never starts with -. All arguments are in ASCII.

See the end of this page for example command-line uses of your program. Neither the examples there nor the examples for indvidual patterns are meant to be exhaustive.

Constraints: Your implementation must be in ANSI C, so that it compiles without errors or extra flags on the CADE lab1-n.eng.utah.edu machines using the default gcc. Your implementation must not depend on any libraries other than the standard C library; please note that while "regex.h" and its associated functions are POSIX-standard, they are not part of ANSI C and therefore not allowed in this assignment. Also, yor implementation must not use multiplication, division, or modulo operators. (Bitwise operations offer alternatives to those operations.) You should hand in one matchlab.c file so that gcc -o matchlab matchlab.c on a CADE lab machine builds your program as matchlab; your program should work the same with and without debugging and optimization options such as -g or -O2. Hand in via Canvas.

Important! Make sure the uID listed at the top of the page is correct, because this assignment (and its correct answer) is uID-specific.

Where the descriptions below say “even position” or “odd position”, counting is from 0, as in C. So, a first character is in an even position.

-a mode
Match a sequence of the following, with nothing else before, after, or in between:

any odd number of repetitions of the letter “c”;
exactly one “=”;
between 2 and 5 repetitions (inclusive) of the letter “r”;
exactly one “,”; and
an odd number of uppercase letters.
For matches, perform the following conversion:

replace each character by the last one.
Example arguments that match, followed by their conversions:

ccc=rrrr,HCA
→ AAAAAAAAAAAA
ccccccccc=rrr,GCE
→ EEEEEEEEEEEEEEEEE
ccccccc=rrr,FEG
→ GGGGGGGGGGGGGGG
c=rrr,G
→ GGGGGGG
c=rrrr,FGE
→ EEEEEEEEEE
c=rr,EEEHE
→ EEEEEEEEEE
ccc=rrr,ECEBC
→ CCCCCCCCCCCCC
ccccc=rrr,BFB
→ BBBBBBBBBBBBB
ccccc=rr,ABC
→ CCCCCCCCCCCC
c=rrr,BBFBE
→ EEEEEEEEEEE
Example arguments that do not match:

.ccc=rrrr,HCA
ccc=rrrr,HCA.
e=rrr,ADBEA
=vvvvvvv,EFA
ccccccccc=wwwwwww_BFG
ccccc,rr:H
ccccccc=oo=B
ccccccc:rr,E
ccccccc=ppppppp,A
ccccccc=rrrr:BGC
ccccccc=rrrr_ADC
ccccccc=rr=BFCHB
rrr,B=ccccccc
rrrr,cccccccccHFE=
-b mode
Match a sequence of the following, with nothing else before, after, or in between:

0 or more repetitions of the letter “g”;
exactly one “,”;
an odd number of uppercase letters — call this sequence X;
3 or more repetitions of the letter “w”;
exactly one “_”;
the same character sequence as X, but reversed; and
between 1 and 3 (inclusive) decimal digits.
For matches, perform the following conversion:

after each character, insert a digit that is the position of the character modulo 8.
Example arguments that match, followed by their conversions:

ggggggg,BEFwwwwwwww_FEB310
→ g0g1g2g3g4g5g6,7B0E1F2w3w4w5w6w7w0w1w2_3F4E5B6371001
ggggggggg,BCCwwwwwwww_CCB157
→ g0g1g2g3g4g5g6g7g0,1B2C3C4w5w6w7w0w1w2w3w4_5C6C7B0115273
gg,Gwwwwwww_G866
→ g0g1,2G3w4w5w6w7w0w1w2_3G4856667
gggg,HGDHFwwwwww_FHDGH189
→ g0g1g2g3,4H5G6D7H0F1w2w3w4w5w6w7_0F1H2D3G4H5168790
ggggg,Ewwwwwww_E891
→ g0g1g2g3g4,5E6w7w0w1w2w3w4w5_6E7809112
gggggggg,GEHwwwwwwww_HEG131
→ g0g1g2g3g4g5g6g7,0G1E2H3w4w5w6w7w0w1w2w3_4H5E6G7103112
ggggggggg,FAFwwwwwwww_FAF794
→ g0g1g2g3g4g5g6g7g0,1F2A3F4w5w6w7w0w1w2w3w4_5F6A7F0719243
gggg,Gwwwwwwww_G142
→ g0g1g2g3,4G5w6w7w0w1w2w3w4w5_6G7104122
gggggg,GGGDHwwwwwwww_HDGGG338
→ g0g1g2g3g4g5,6G7G0G1D2H3w4w5w6w7w0w1w2w3_4H5D6G7G0G1323384
ggggggggg,AEFwwwwwww_FEA843
→ g0g1g2g3g4g5g6g7g0,1A2E3F4w5w6w7w0w1w2w3_4F5E6A7804132
Example arguments that do not match:

.ggggggg,BEFwwwwwwww_FEB310
ggggggg,BEFwwwwwwww_FEB310.
dd,ECDFBpppp_CF204
ll,AEEBGyyyyyyy_GBEEA473
gg:GFDBFwwwwwwwww_FBDFG348
gggggg,GDBDFwwwwww:FDBDG373
gggggggg,HEFCEttttttttt_ECFEH513
g,FHBttttttttt_BHF452
g,Ewwwwwww:E575
ggg=FGCwwwwww_FGCFGCFGCFGC323
gggg=Cwwwwwwwww_C423
ggg,FDBrrrrrrrrr_BDF46
665wwwwwwwggggggggg_FCA,ACF
_CHEGHHGEHCgggggggwwwwwwww720,
-c mode
Match a sequence of the following, with nothing else before, after, or in between:

any odd number of repetitions of the letter “j”;
exactly one “_”;
an odd number of uppercase letters — call this sequence X;
any odd number of repetitions of the letter “u”;
exactly one “_”;
the same characters as the odd-positioned characters in X; and
between 1 and 3 (inclusive) decimal digits.
For matches, perform the following conversion:

remove every “E” and “G”.
Example arguments that match, followed by their conversions:

jjj_Euuuuu_748
→ jjj_uuuuu_748
jjjjjjjjj_AAHu_A269
→ jjjjjjjjj_AAHu_A269
jjjjjjj_Au_180
→ jjjjjjj_Au_180
jjjjjjjjj_EBDu_B187
→ jjjjjjjjj_BDu_B187
j_Eu_312
→ j_u_312
j_Duuuuuuuuu_618
→ j_Duuuuuuuuu_618
jjj_Cuuuuuuuuu_277
→ jjj_Cuuuuuuuuu_277
jjj_EBHDHuuuuu_BD912
→ jjj_BHDHuuuuu_BD912
j_Fu_629
→ j_Fu_629
jjjjj_BGHu_G931
→ jjjjj_BHu_931
Example arguments that do not match:

.jjj_Euuuuu_748
jjj_Euuuuu_748.
iiiiiii=CDHDAwwwwwwwww_DD886
hh_HGGuuu_G892
jjjjjjj_HBDuuuuu,B307
j_BDDrr_D81
jjj_HGAvvvvvvv=G998
jjjjj_ACFEGqqqqqq_CE688
aaaaaaaa_CCEuuuuuuu_C526
j_FEEBHuuuuu_FEEBHFEEBHFEEBH736
jjj_HHBFFppppp_HF498
cc_Eu,952
_Buuuuuuuuu505_jjjjjjj
Huuuuu__jjjjjjjjj652
Examples
Assuming that your program is created as ./matchlab, here are some example command-line uses (where “$” is a command-line prompt). We expect your program to match this output exactly.

$ ./matchlab ccccccc=rrrr,GHG
yes
$ ./matchlab ccc=ppppppp:DAH
no
$ ./matchlab ccccccc=rrrr,GHG ccc=ppppppp:DAH
yes
no
$ ./matchlab -t ccccccc=rrrr,GHG
GGGGGGGGGGGGGGGG
$ ./matchlab -t ccc=ppppppp:DAH ccccccc=rrrr,GHG
GGGGGGGGGGGGGGGG
$ ./matchlab -t ccccccc=rrrr,GHG ccccc=rrrr,C
GGGGGGGGGGGGGGGG
CCCCCCCCCCCC
$ ./matchlab -t -b gg,Cwwwwwwwww_C606
g0g1,2C3w4w5w6w7w0w1w2w3w4_5C6670061
$ ./matchlab -c -t jjjjjjjjj_GEHuuuuuuu_E914
jjjjjjjjj_Huuuuuuu_914
$ ./matchlab -c jjjjjjjjj_GEHuuuuuuu_E914
yes