How programs are compiled or interpreted in Intro to Computing - Draw the Process

Draw This - beginner

Draw a flowchart that shows the steps a program goes through when it is compiled versus when it is interpreted. Include the source code, compilation or interpretation process, and the final output execution.

10 minutes

Hint 1

Hint 2

Hint 3

Hint 4

Hint 5

Grading Criteria

Start and End symbols (ovals) present for Source Code and Program Output

Two separate paths shown: one for compilation, one for interpretation

Compilation path includes 'Compile Program', 'Machine Code', and 'Run Machine Code' steps

Interpretation path includes 'Interpret Program' and 'Execute Line by Line' steps

Arrows correctly show flow from source code to output

No missing steps in either path

Solution

  +----------------+
  |  Source Code   |
  +--------+-------+
           |
    +------+-------+----------------+
    |                              |
+---v---+                    +-----v-----+
|Compile|                    |Interpret  |
|Program|                    |Program    |
+---+---+                    +-----+-----+
    |                              |
+---v---+                    +-----v-----+
|Machine|                    |Execute    |
|Code   |                    |Line by    |
+---+---+                    |Line       |
    |                        +-----+-----+
+---v---+                          |
|Run    |                          |
|Machine|                          |
|Code   |                          |
+---+---+                          |
    |                              |
    +--------------+---------------+
                   |
           +-------v-------+
           | Program Output|
           +---------------+

This flowchart starts with the Source Code as the input.

There are two main paths:

• Compilation path: The source code is first compiled into machine code, which is a low-level code the computer understands directly. Then, the machine code is run by the computer's processor. This produces the program output.
• Interpretation path: The source code is interpreted line by line by an interpreter program. Each line is executed immediately without creating a separate machine code file. This also produces the program output.

Both paths end with the Program Output, which is what the user sees or the result of running the program.

Variations - 2 Challenges

[intermediate] Draw a flowchart showing how a program written in a compiled language is transformed from source code to output, including error checking during compilation.

[advanced] Draw a detailed flowchart comparing how a program is executed in a compiled language versus an interpreted language, including the role of the compiler, interpreter, and runtime environment.

Practice

1. What is the main difference between a compiler and an interpreter?

easy

A. A compiler translates the whole program before running; an interpreter translates line by line during execution.

B. A compiler runs the program line by line; an interpreter translates the whole program first.

C. A compiler only checks for errors; an interpreter runs the program without translation.

D. A compiler and interpreter do the same thing in the same way.

Solution

1. Step 1: Understand compilation

   A compiler translates the entire program into machine code before any part runs.

2. Step 2: Understand interpretation

   An interpreter reads and executes the program line by line during runtime.

3. Final Answer:

   A compiler translates the whole program before running; an interpreter translates line by line during execution. -> Option A

4. Quick Check:

   Compilation = whole program first, Interpretation = line by line [OK]

Hint: Compiler = all at once; Interpreter = step by step [OK]

Common Mistakes:

• Confusing which translates first
• Thinking both do the same thing
• Believing interpreters translate whole program first

2. Which of the following is the correct way to describe an interpreter's process?

easy

A. It only checks syntax without running the code.

B. It converts the entire program into machine code before execution.

C. It compiles code into an executable file.

D. It reads and executes code one line at a time.

Solution

1. Step 1: Recall interpreter behavior

   An interpreter reads and executes code line by line during runtime.

2. Step 2: Compare options

   Only It reads and executes code one line at a time. correctly describes this process.

3. Final Answer:

   It reads and executes code one line at a time. -> Option D

4. Quick Check:

   Interpreter = line-by-line execution [OK]

Hint: Interpreter = line-by-line execution [OK]

Common Mistakes:

• Mixing up compilation and interpretation
• Thinking interpreter creates executable files
• Assuming interpreter only checks syntax

3. Consider this flowchart for running a program:



Which method does this flowchart represent?

medium

A. Interpreting

B. Scripting

C. Compiling

D. Debugging

Solution

1. Step 1: Analyze flowchart steps

   The flowchart shows compiling the whole program before running it.

2. Step 2: Match to method

   This matches the compiling process, not interpreting or others.

3. Final Answer:

   Compiling -> Option C

4. Quick Check:

   Compile = whole program first [OK]

Hint: Compile = whole program before run [OK]

Common Mistakes:

• Confusing compile with interpret
• Thinking debugging is shown
• Assuming scripting means compiling

4. A student wrote this code to explain interpretation:

print('Hello')
print('World')

They said the interpreter runs both lines at once. What is the error?

medium

A. Interpreters run code line by line, not all at once.

B. Interpreters cannot run print statements.

C. The code has a syntax error.

D. Interpreters only run one line of code total.

Solution

1. Step 1: Understand interpreter execution

   Interpreters execute code one line at a time, not simultaneously.

2. Step 2: Identify student's mistake

   The student incorrectly said both lines run at once, which is wrong.

3. Final Answer:

   Interpreters run code line by line, not all at once. -> Option A

4. Quick Check:

   Interpreter = line-by-line execution [OK]

Hint: Interpreter = one line at a time [OK]

Common Mistakes:

• Thinking interpreter runs all code simultaneously
• Believing print can't run in interpreter
• Confusing syntax errors with execution method

5. You have a program that must run on many different computers without installing extra software. Which method is better and why?

Options:
A) Compile the program into machine code for each computer.
B) Use an interpreter so the program runs line by line on any computer with the interpreter.
C) Compile once on your computer and send the executable.
D) Neither; rewrite the program in assembly language.

hard

A. Compile separately for each computer to ensure compatibility.

B. Use an interpreter so the program runs on any computer with the interpreter installed.

C. Compile once and send executable; it will run on all computers.

D. Rewrite in assembly language for best performance.

Solution

1. Step 1: Consider compatibility needs

   Compiling creates machine code specific to one computer type, so compiling separately is needed for each.

2. Step 2: Evaluate interpreter advantage

   An interpreter allows running the same code on any computer with the interpreter installed, improving portability.

3. Step 3: Analyze other options

   Compiling once won't work on all computers due to different architectures; rewriting in assembly is complex and not portable.

4. Final Answer:

   Use an interpreter so the program runs on any computer with the interpreter installed. -> Option B

5. Quick Check:

   Interpreter = portability across computers [OK]

Hint: Interpreter = runs anywhere with interpreter installed [OK]

Common Mistakes:

• Assuming one compiled file runs everywhere
• Ignoring interpreter installation requirement
• Thinking assembly is portable