Variables and Data types 1 Suppose you are writing a program

Variables and Data types.

1. Suppose you are writing a program to calculate a student\'s GPA A pseudocode version of such a program is the following: Start: Grade for COS 198 = 4.0; Number of hours for cos 198 = 3; Grade for MAT 126 = 3.5; Number of hours for MAT 126 = 4; Grade for ENG 101 = 4.0; Number of hours for ENG 101 = 3; Grade for PSY 100 = 3.5; Number of hours for PSY 100 = 3; Sum = (Grade for COS 198) * (Number of hours for cos 198) + (Grade for MAT 126) *(Number of hours for MAT 126) + (Grade for ENG 101) * (Number of hours for ENG 101) + (Grade for PSY 100) (Number of hours for PSY 100) Attempted = (Number of hours for COS 198) + (Number of hours for MAT 126) + (Number of hours for ENG 101) + (Number of hours for PSY 100); GPASum/Attempted; End What would you name the variables in the program if you were programming in: (a) A language that allows variable names that are a single letter followed by o, 1, or 2 digits? variable names beginning with a letter? with all variable names beginning with a letter? (b) A language with a 20-character limit on variable names, with all (c) A language with no limit on the length of variable names, and 2. Assume that the following statements are in sequence in a pro- gram (e.g., if statement 1 gives a variable a new value, the variable

Solution

1

(a) Grades --- g1,g2,g3,g4

hours -h1,h2,h3,h4

sum ---- S

Attempted --A

GPA --- G

(b)

Grades --- gradeCOS,gradeMAT,gradeENG,gradePSY

hours -hrsCOS,hrsMAT,hrsENG,hrsPSY

sum ---- SUM

Attempted --Attempt

GPA --- SUM/Attempt

(c)

Grades --- gradeCOS198,gradeMAT126,gradeENG101,gradePSY100

hours -hrsCOS198,hrsMAT126,hrsENG101,hrsPSY100

sum ---- SUM

Attempted --Attemptedverage

GPA --- SUM/Attempted

2. A=B=C =0

A:=5 ; A=5

B:=A+C ; B= 5

C:= B+C; C =5

A:= 2+A ; A=2+5 =7

B:= A+B+C; B=7+5+5 = 17

3.

UNSIGNED INTEGERS

ADVANTAGES

Disadvantages

4

a) m+22

b)m+23

c)m+3

5

Address = BaseAddress + ((depthindex*colsize+colindex) * rowsize + rowindex) * ElementSize

Temp[40][30][20] = BaseAddress + ((depthindex*colsize+colindex) * rowsize + rowindex) * ElementSize

Now we have BaseAddress = m ,Elementsize = 4 bytes ,Colsize = 100 ,Rowsize = 100,Depthindex = 40

Colindex = 30 ,Rowindex = 20

Address = m + ( (40*100 + 30)*100 + 20 ) * 4 bytes

= m + ( (4030)*100 + 20 ) * 4 bytes

= m + (403020) * 4 bytes = m + 1612080