Instructor: P eter C hen

Introduction to Programming with QBasic to Visual Basic Lecture 8 Instructor:PeterChen CSIT 208, Section 3230

CLS INPUT “Enter the name of a corporation: “, corp$ LET foundFlag = 0 LET first = 1 LET last = 100 DO WHILE (first <= last) AND (foundFlag = 0) LET middle = INT(first + last)/2) SELECT case firm&(middle) CASE corp$ LET foundFlag = 1 CASE IS > corp$ LET first = middle – 1 CASE IS < corp$ LET first = middle + 1 END SELECT LOOP IF foundFlag = 1 THEN PRINT corp$; “ found” ELSE PRINT corp$; “ not found” END IF END Binary Search Assume the array firm$() contains the Alphabetized names Of 100 corporations * Page 267 CSIT 208, Section 3230

CLS DIM rm ( 1 TO 4, 1 TO 4) CALL ReadMileages(rm()) CALL ShowCitites CALL ShowMileage(rm(), row, col) DATA 0, 2054, 802, 738 DATA 2054, 0, 2786, 2706 DATA 802, 2786, 0 ,100 DATA 738, 2706, 100, 0 END SUB InputCities (row, col) INPUT “Origin”; row INPUT “Destination”; col END SUB Two-Dimensional Arrays * Page 276 Continue … CSIT 208, Section 3230

SUB ReadMileages (rm()) FOR row = 1 TO 4 FOR col = 1 TO 4 READ rm (row, col) NEXT col NEXT row END SUB SUB ShowCities PRINT “1. Chicago” PRINT “2. Los Angeles” PRINT “3. New York” PRINT “4. Philadelphia” END SUB SUB ShowMileage (rm(), row, col) PRINT “ The road mileage is”; rm(row, col) END SUB CSIT 208, Section 3230

Exercise Please add one more destination, (5. San Francisco) Distance: San Francisco  Chicago, 1500 San Francisco  Los Angeles, 200 San Francisco  New York, 4000 San Francisco  Philadelphia, 3500 CSIT 208, Section 3230

Chapter 8 - WRITE Statement CLS WRITE “Eric” WRITE 1946 WRITE “Eric”, 1946 LET a$ = “John” LET b$ = “Smith” WRITE 14 * 139, “J.P “ + a$, b$, “Amy” END * Page 303 CSIT 208, Section 3230

Sequential File OPEN “YOB.DAT FOR OUTPUT AS #1 READ name$, year DO WHILE name$ <> “EOD” WRITE #1, name$, year READ name$, year LOOP CLOSE #1 DATA Barbara, 1942 DATA Ringo, 1940 DATA Sylvester, 1946 DATA EOD, 0 END * Page 304 CSIT 208, Section 3230

Exercise Write a program to create the file “student.dat”. Use EOD as a sentinel to indicate that all the data have been read. Please input three student’s first name, last name, and ID Number. CSIT 208, Section 3230

Adding Items to a Sequential File CLS OPEN “YOB.DAT” FOR APPEND AS #1 INPUT “Name, Year of Birth”; name$, year WRITE #1, name$, year CLOSE #1 END CSIT 208, Section 3230

Exercise Write a program to append John Smith, ID number: 7773 into the student.dat file. CSIT 208, Section 3230

Instructor: P eter C hen