›            AREA CODE 1997›           By Frank Walters› › This  utility  program  displays  the› State   or   Province   (Canada)  and› selected  cities  for  each telephone› area  code entered. Press [Return] at› the prompt to end program.› › The  purpose  of this text file is to› explain  how to update the program to› add  new  area  codes  as they become› available.  The program uses RESTORE,› READ  and  DATA functions of BASIC to› find  the  area code information. The› line  numbers represent AREA CODES so› this    program   should   never   be› re-numbered.› › The  main  program is in lines 10-70,› with a continuous loop between 20 and› 70.  The  user  inputs  the area code› into   AC$.  AC$  is  converted  from› string variable to a numeric variable› with V=VAL(AC$) expression.› › Line  50  RESTORE  V  will reset data› pointer  to first DATA line beginning› with  desired  area code. Here is the› format of each data line:› › LINE NUMBER is the AREA CODE.› DATA   items   start  with  a  number› representing  total  number  of  DATA› items  FOLLOWING the number. The next› item is the STATE or PROVINCE name in› upper case, followed by a comma and a› space.  All additional items are city› names  in Upper/lower case, preceeded› by  a  space  in  order to indent the› city  list  below  the  state name on› screen. Example:› › 315 DATA 3,NEW YORK, Syracuse, Utica› › Area  Code  315 contains 3 DATA items› after  the  "3" item:  NEW YORK state› followed by two cities. Therefore the› first DATA item is the number "3".› › In   order  to  protect  the  RESTORE› method from invalid area code inputs,› you  must preceed each group of valid› line numbers with a "nothing" line:› › 200 DATA 1,nothing› › Any  number equal to or less than 200› will  READ  line  200 and display the› "nothing"   information.   In   other› words,  any blank line (no area code)› must  have  a similar DATA entry like› line  200.  In the case of a sequence› of  invalid  line  numbers,  only the› highest  invalid  line needs the DATA› statement  as above since the RESTORE› statement will restore the pointer to› the  first  DATA  line  following the› input number.› › To   add  a  new  area  code  to  the› program, simply add a new line number› with   that  area  code.  Follow  the› sequence  of  the  other lines with a› "number", STATE or PROVINCE, and City› or  list of selected cities. Make the› number equal to the total cities plus› one  for the state name. Don't forget› the SPACE in front of each City name.› If  the line number one less than the› new  area code is missing, then add a› new  line with the DATA exactly as in› line 200.› › EXAMPLE:› › 275 DATA,4,STATE, City1, City2, Town› › Line 274 is missing so we must add:› › 274 DATA 1,nothing› › For   standardization  purposes,  the› cities  are  listed  in  alphabetical› order in each DATA line.› › Area  code  275  will  then look like› this on screen after user entry:› › Area Code: 275› › STATE›  City1›  City2›  Town› › You  may  have  to edit the cities in› other  DATA lines when new area codes› are  added,  since  one area is often› divided into two new ones.› › Just  change  the date in line 2 when› changes are made.› › Frank Walters› T.A.C.O. Bell BBS› 03/20/97› ›              o=o=o=o=o=›