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 within the main() Function 😊.

Program Control is with the main() Function

number = int(input(“Enter an Integer Number: “))

Print Message on the Output Screen and take an Integer Number as Input from User

number = 6

(In main() Function)

Enter an Integer Number: 6

result = square04(number)

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., square04(). Note that square04() is a Function Call.
• Step 2:  Once Function Call (i.e., square04()) is complete, it will return an Integer value on RHS OF THE Assignment Statement i.e., square04() 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

number = 6 

(In main() Function)

result 

(In main() Function)

Enter an Integer Number: 6

• result = square04()

·        Step 1:  Execute Right Hand Side (RHS) of the Assignment Statement i.e., square04(). Note that   square04() is a Function Call.

·        This Python Statement is a Function Call. Therefore, Program Control will move from Calling Function (main()) to the Called Function (square04()).

Program Control is with the  square04() Function

Function Header – square04() Function

• Program Control is with the square04() Function 

• • Function Header 

• • • Step 1: Declare a Variable number 
    • Step 2: Store Value (i.e., 6) Passed by Calling Function (i.e., main() Function) in the Variable number (declared in Step 1)

        –

         –

number = 6 

(In main() Function)

result 

(In main() Function)

number = 6

(In square04() Function)

Enter an Integer Number: 6

Body of Function – square04() Function

result = number * number

Multiply number with itself (to calculate its square) and store result in a variable (called result)

• Calculation

·        result = number * number

·        result = 6 * 6

·        result = 36

• Note

·        In the calculation we have used the Variable number (In square04() Function)

number = 6 

(In main() Function)

result 

(In main() Function)

number = 6 

(In square04() Function)

result = 36 

(In square04() Function)

Enter an Integer Number: 6

return result

This Statement will RETURN the Value stored in Variable result (i.e., 36) to the Calling Function (i.e., main() Function)

number = 6 

(In main() Function)

result 

(In main() Function)

number = 6 

(In square04() Function)

result = 36 

(In square04() Function)

Enter an Integer Number: 6

Body of square04() Function is completely executed. Variables declared in the square04() Function will be destroyed and Program Control will move back from the Called Function (square04()) to the Calling Function (main())

Program Control is with the main() Function

number = 6 

(In main() Function)

result 

(In main() Function)

Enter an Integer Number: 6

result = square04()

• Step 1:  Once Function Call (i.e., square04()) is complete, it will return an Integer value on RHS of the Assignment Statement i.e., square04() will be replaced with the Returned Value
• result = 36
• Step 2:  Store the Returned Value (Step 2) in the Variable result on the Left Hand Side (LHS) of the Assignment Statement

result = square04(number)

Store the Integer Value (Output) Returned by square04() in Variable result

• Calculation

·        result = square04()

·        result = 36

number = 6 

(In main() Function)

result = 36

(In main() Function)

Enter an Integer Number: 6

print(“Square of”, number,”*”,number,”=”, result)

Print number (Input) on the Output Screen. Note that we are displaying number (Input) in the square04() Function because Input was taken from user in square04() and main() Function does not know about Input

number = 6 

(In main() Function)

result = 36

(In main() Function)

Enter an Integer Number: 6

Square of 6 = 36

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  Therefore, Python Program will be Terminated 😊

        –

         –

        –

Enter an Integer Number: 6

Square of 6 = 36

Step 7: Analysis, Main Findings and Conclusion

Step 7.1: Analysis of Python Program – Calling a Function (Return Type, Arguments / Parameters)

Note the Function Prototype, Function Header and Function Call 

• Function Prototype 

• • void square04(number);
• Function Header
  • def square04(number):   
• Function Call
  • square04(number)
• Analysis 
  • The square04(number) Function takes an Arguments / Parameters and 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 takes an Arguments / Parameters and Return a Value, in Function Call we use
    • Function Name with ()

Step 7.2: Summary of Analysis – Calling a Function (Return Type and Arguments / Parameters)

Step 7.3: Main Findings

• Alhamdulillah (الحمدللہ) 😊, square04(number) Function efficiently and effectively performed our required Programming Task i.e.
  • Calculating and Displaying Square of an Integer Number on the Output Screen

Step 7.4: Conclusion

• To conclude, our main goal i.e.,
  • Calculating and Displaying Square of an Integer Number on the Output Screen was successfully accomplished using square04(number) Function. Alhamdulillah (الحمدللہ) ��