Chapter 5 Overheads

PROBLEM :

WHAT WAS THE CLASS AVERAGE ON THE LAST TEST IN MY ENGLISH CLASS?

UNDERSTAND THE PROBLEM

SURE: ADD UP ALL OF THE GRADES AND DIVIDE BY THE NUMBER OF STUDENTS

TOP DOWN DESIGN

INPUT :	TEST GRADES (HOW MANY?) THEY MUST BE COUNTED
OUTPUT :	THE CLASS AVERAGE THE NUMBER OF STUDENTS WHO TOOK THE TEST

LEVEL 0 :

WHILE MORE GRADES

GET GRADE (grade)
ADD TO SUM (sum)
INCREMENT STUDENT COUNT (count)

COMPUTE AVERAGE
PRINT AVERAGE

LEVEL 1 :

GET GRADE

READ( GRADE )

ADD TO SUM

SUM is SUM + GRADE

INCREMENT STUDENT COUNT

COUNT is COUNT + 1

COMPUTE AVERAGE

AVG = SUM / COUNT

PROGRAM GRADES( INPUT, OUTPUT );

VAR


GRADE, SUM, COUNT, AVERAGE : INTEGER;

BEGIN


SUM := 0;

    COUNT := 0;

    READ( GRADE );

    WHILE NOT EOF DO
    
    
    BEGIN
        
        
        SUM := SUM + GRADE;

            COUNT := COUNT + 1;

            READ( GRADE );
        
        END;
    
    AVERAGE := SUM DIV COUNT;

    WRITELN('THE CLASS AVERAGE FOR ', COUNT, 'STUDENTS IS ', AVERAGE)

END.

CONTROL STRUCTURE:

WHILE MORE GRADES

WHILE NOT EOF DO

BEGIN

END

NOTE :

EOF RETURNS TRUE IT THERE IS NO MORE DATA.

ANYTHING ELSE TO BE NOTED?

SUM AND COUNT MUST BE SET TO ZERO FOR THE PROCESS TO WORK.

SUMMARIZE

BOOLEAN EXPRESSIONS

EOF

BOOLEAN FUNCTION
RETURNS: TRUE or FALSE

REPETITION (LOOP)

WHILE BOOLEAN EXP. DO

STATEMENT

WHILE BOOLEAN EXP. DO

BEGIN
  .
  .
  .
END