Step 6: Dry Run the Python Program

Python Statement

Processing

Memory

Output Screen

Start (Program Execution) – Execution of Python Program starts from the main() Function. Therefore, Program Control will be with the main() Function 😊

Program Control is with the main() Function

result = grade_calculation3()

This Python Statement is an Assignment Statement and will be executed in the following Three Steps.

• Step 1:  Execute Right Hand Side (RHS) of the Assignment Statement i.e.,  grade_calculation3(). Note that   grade_calculation3() is a Function Call.
• Step 2:  Once Function Call (i.e.,  grade_calculation3()) is complete, it will return a character on RHS OF THE Assignment Statement i.e.,  grade_calculation3() will be replaced with the Returned Value
• Step 3:  Store the Returned Value (Step 2) in the Variable result on the Left Hand Side (LHS) of the Assignment Statement

result =

(In main() Function)

–

• result =  grade_calculation3()

·        Step 1: Execute Right Hand Side (RHS) of the Assignment Statement i.e.,  grade_calculation3(). Note that grade_calculation3() is a Function Call.

·        This Python Statement is a Function Call. Therefore, Program Control will move from Calling Function (main()) to the Called Function ( grade_calculation3()).

Program Control is with the  grade_calculation3() Function

marks = float(input(“Enter your marks in Math: “))

Print Message on the Output Screen and take Marks as Input from User

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

The next Python Statement is a nested Selection Structure. There are two Possible Outcomes of a Condition: (1) True or (2) False.

• If the Condition is True, Python Statements immediately after the Condition will be executed and Program Control will exit from the nested Selection Structure
• If the Condition is False, Python Statements immediately after the Condition will be skipped and Program Control will move to the next Condition in the nested Selection Structure

IF marks >= 80 and marks <= 100:

Check whether the Condition is True or False

• Preprocessing

·        70.5 >= 80 and 70.5 <= 100

·        False and False

·        False

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘A’) will be skipped and Program Control will move to the next Condition in the nested Selection Structure

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

grade – ‘A’

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘A’) will be skipped

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

ELIF marks >= 70 and marks < 80:

Check whether the Condition is True or False

• Preprocessing

·        70.5 >= 70 and 70.5 < 80

·        True and True

·        True

The Condition is True, Python Statements immediately after the Condition will be executed and Program Control will exit from the nested Selection Structure

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

grade – ‘B’

Store B in Variable grade (and exit from the nested Selection Structure)

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

ELIF marks >= 60 and marks < 70:

Check whether the Condition is True or False

• Preprocessing

·        70.5 >= 60 and 70.5 <= 70

·        False and False

·        False

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘C’) will be skipped and Program Control will move to the next Condition in the nested Selection Structure

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

grade – ‘C’

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘C’) will be skipped

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

ELIF marks >= 50 and marks < 60:

Check whether the Condition is True or False

• Preprocessing

·        70.5 >= 50 and 70.5 < 60

·        False and False

·        False

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘D’) will be skipped and Program Control will move to the next Condition in the nested Selection Structure

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

grade – ‘D’

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘D’) will be skipped

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

ELIF marks >= 0 and marks < 50:

Check whether the Condition is True or False

• Preprocessing

·        70.5 >= 0 and 70.5 < 50

·        False and False

·        False

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘F’) will be skipped and Program Control will move to the next Condition in the nested Selection Structure

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

grade – ‘F’

The Condition is False,  Python Statements immediately after the Condition (i.e., grade = ‘F’) will be skipped

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

print(“Your Marks in Math are: “,marks)

Print Marks (Input) on the Output Screen.

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

print(“You Grade in Math is: “, grade)

Print Grade (Output) on the Output Screen.

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

return grade

This Statement will RETURN the Value stored in Variable grade (i.e., B) to the Calling Function (i.e., main() Function)

result =

(In main() Function)

marks = 70.5

(In  grade_calculation3() Function)

grade = B

(In  grade_calculation3() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

Body of grade_calculation3() Function is completely executed. Variables declared in the grade_calculation1() Function will be destroyed and Program Control will move back from the Called Function ( grade_calculation3()) to the Calling Function (main())

Program Control is with the main() Function

–

–

result = B

(In main() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

result =  grade_calculation3()

• Step 1:  Once Function Call (i.e.,  grade_calculation3()) is complete, it will return a Float value on RHS of the Assignment Statement i.e.,  grade_calculation3() will be replaced with the Returned Value
• result = B
• Step 2:  Store the Returned Value (Step 2) in the Variable result on the Left Hand Side (LHS) of the Assignment Statement

result =  grade_calculation3()

Store the Character (Output) Returned by  grade_calculation3() in Variable result

• Calculation

·        result =  grade_calculation3()

·        result = B

result = B

(In main() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

print(result)

Print Output (Grade) on the Output Screen.

result = B

(In main() Function)

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

End (Program Execution): Python Program will terminate when all the Python Statements in the main() Function are executed. 

As can be noted, all the Python Statements in the main() Function are executed.  Variables declared in the main() Function will be destroyed and Python Program will be Terminated 😊

–

–

–

Enter your marks in Math: 70.5

Your Marks in Math are: 70.5

You Grade in Math is: B

Step 7: Analysis, Main Findings and Conclusion

Step 7.1: Analysis of Python Program – Calling a Function (No Return Type, No Arguments / Parameters)

• Note the Function Prototype, Function Header and Function Call 
• Function Prototype 
  • char grade_calculation3();
• Function Header
  • def grade_calculation3():   
• Function Call
  • grade_calculation3()
• Analysis 
  • The grade_calculation3() Function does not take any Argument / Parameter but Return a Value, which is evident from 
    • RETURN statement
• In Function Prototype, Function Header and Function Call, we have () Brackets i.e., 
  • Function Header and Function Call Matches Function Prototype 
• Conclusion 
  • When a Function does not take any Arguments / Parameters but Return any Value, in Function Call we use
    • Function Name with ()

Step 7.2: Summary of Analysis – Calling a Function (No Return Type, No Arguments / Parameters)

Step 7.3: Main Findings

• Alhamdulillah (الحمدللہ) 😊, grade_calculation3() Function efficiently and effectively performed our required Programming Task i.e.
  • Calculating and Displaying Grade of a Student in Math on the Output Screen

Step 7.4: Conclusion

• To conclude, our main goal i.e.
  • Calculating and Displaying Grade of a Student in Math on the Output Screen was successfully accomplished using grade_calculation3() Function. Alhamdulillah (الحمدللہ)