PROGRAM Factorial; VAR Number, Index: integer; Result: longint;

1. Midterm 2: problem 1 PROGRAM Factorial; VAR Number, Index: integer; Result: longint; BEGIN writeln('Enter an integer'); readln(Number); Result := 1; IF Number > 1 THEN FOR Index := 1 TO Number DO Result := Result * Index; writeln ('The factorial is ', Result); END. Declaration: 2 Input: 2 Overall layout: 2 Initialization: 3 Calculation: 2 IF THEN: 2 FOR LOOP: 2 overall correct: 4 Output: 1

2. PROGRAM LetterCount; {Program counts the number of letters in a sentence} CONST Period = '.'; VAR letters, vowels, blanks: integer; Ch: char; BEGIN letters := 0; vowels := 0; blanks := 0; writeln('Write a sentence and end it with a period.'); read(Ch); WHILE Ch <> Period DO BEGIN CASE Ch OF ' ': inc(blanks); {inc(blank) is the same as blank := blank +1} 'a'..'z','A'..'Z': BEGIN inc(letters); IF CH IN ['a','e','i','o','u','A','E','I','O','U'] THEN inc (vowels); END; END; {CASE} read(Ch); END; {WHILE} writeln('The number of blanks is ', blanks); writeln('The number of letters is ', letters); writeln('The number of vowels is ', vowels); END. Declarations: 3 initializations: 2 initialize Ch: 1 WHILE loop:2 CASE: 2 vowels:1 overall correctness: 6 output: 2 Overall layout: 1

3. PROCEDURE Second_Largest (VAR Second : integer); VAR First, Current : integer; BEGIN First := 0; {initialize } Second := 0; read (Current); WHILE NOT (Current = 0) DO BEGIN IF Current > First THEN BEGIN Second := First; First := Current END ELSE IF Current > Second THEN Second := Current; read(Current); END {while} END; {procedure second_largest} initialize values: 1 overall logic of WHILE loop: 1 logic for largest value: 1 logic for second largest value: 1 If the entire program would work correctly:1

4. Midterm 2 • 90-100 20 • 80-89 10 • 70-79 9 • 65-69 3 • 0-64 14

5. Complex data types • Complex data types: a data type made of a complex of smaller pieces. Pascal has four very commonly used complex data types: strings, array, records and objects. • We have already covered strings, will cover arrays in the next few calsses and will not cover records or objects.

6. TYPE • The reserved word TYPE introduces new types in Pascal. One new type you can define is an array. • The format of a type definition is:TYPE IntArray = ARRAY[1..5] OF integer;This definition would produce a new type ‘IntArray’ which would consist of an array of memory locations (5 of them) which store integers.

7. TYPE IntArray = ARRAY[1..5] OF integer; • TYPE: tells compiler we are defining a new type • IntArray: The name of the new type (name must conform to rules for naming an identifier) • ARRAY: tells compiler the new type will be an array • [1..5]: 1 will be lowest subscript; 5 will be highest. Both numbers must be same ordinal type. (Called dimensioning an array) • OF integer: means the array will store values of type integer (an array can only store one type).

8. Once a new type is defined, you can declare a variable to hold the type like you do for a simple type. For example:VAR MyArray, YourArray: IntArray;would create two new identifiers (MyArray and YourArray) both of type IntArray. Each identifier can now hold 5 integers.

9. How do we access the values? • To access the first value of MyArray, we would write: MyArray[1] • This would be used as any other simple variable would be used. • The 1 between the brackets is called a subscript. You can also use variable identifiers as subscripts (this makes arrays very useful).