added piazza comments to debugging

ref/debugging.md

@@ -9,12 +9,232 @@ seo:
 ---
 
 # 🐛 Debugging scenarios and solutions
+The majority of this cases were provided by the students of previouse qarters. You are wellcome to contribute your errors as well.
+
+
+## Case 1. `print`
+*   Correct line of code: `print("Hello, World")`
+
+### Syntax error
+*   Error #1: `SyntaxError: unexpected EOF while parsing`
+*   Erroneous code:
+```py
+print('Hello, World'
+```
+*   **Cause**:  Missing a closing parenthesis `)`.
+
+### EOL
+*   Error #2: `EOL while scanning string literal`
+*   Erroneous code:
+```py
+print('Hello, World)
+```
+or
+```py
+print('Hello, World")
+```
+*   **Cause**:   Missing a **closing** quotation mark or a mismatched quotation mark (incorrectly placed quotation can also cause it).
+
+### Syntax error
+*   Error #3: `SyntaxError: invalid syntax`
+*   Erroneous code:
+```py
+print(Hello World')
+print'Hello World  
+print(Hello World) # see also Error 4
+```
+
+*   **Cause**:   Missing **opening** quotation mark or **opening** parenthesis or quotations around the text.
+
+### Name Error
+*   Error #4: `NameError: name 'Print' is not defined`
+*   Erroneous code:
+```py
+Print('Hello, World')
+```
+
+*   **Cause**:   In this case, an accidentally capitalized name of the function. Generally, this error happens when a function name or a variable name is misspelled or have not been properly defined.
+
+This error can also be caused if there is a **single word** (or comma-separated words) inside the `print` that needed to be displayed as the literal text but does not include quotation marks around it (similar to Error #3).
+
+*   Erroneous code: 
+```
+print(Hello)
+print(Hello, World)
+```
+
+generates the same error (`NameError: name 'Hello' is not defined`), since Python is now looking for a variable called `Hello`, since it doesn’t know that we just forgot to put quotation marks around the text.
+
+### Syntax error
+*   Error #5: `SyntaxError: unmatched ')'`
+*   Erroneous code:
+```py
+print('Hello, World'))
+```
+
+*   **Cause**:  an extra **closing** parenthesis `)` that does not have a matching **opening** paren `(`.
+
+### Strange print results
+*   Error #6: Function Address gets printed - `<function function_name at 0x....> `
+*   Erroneous code:
+```py
+def area(radius):
+    return 3.14 * radius * radius
+
+radius = float(input())
+print(f"Circle has area {area} inches squared.")
+```
+*   **Cause**:  Calling function without the parameters in brackets ( ). For example, area function should be called as - **area(radius)**
+
+## Case 2. Dictionary
+*   Correct code: 
+```py
+dict1 = {"A":1, "B":2, "C":3}
+print(dict1["A"])
+```
+### NameError
+*   Error #1: `NameError: name 'A' is not defined`
+*   Erroneous code:
+```py
+dict1 = {"A":1, "B":2, "C":3}
+print(dict1[A])
+```
+*   **Cause**:  Missing quotation marks (" ") when calling a key from dictionary.
+
+
+## Case 4. `print` with indents
+*   Correct code: 
+```py
+print("Hello world!")
+print("What a nice day!")
+```
+### Indentation Error
+*   Error #1: `IndentationError: unexpected indent`
+*   Erroneous code:
+```py
+print("Hello world!")
+    print("What a nice day!")
+```
+*   **Cause**:   Indented even though it is not necessary. 
+
+
+## Case 5. Function definitions
+*   Correct code: 
+```py
+def first_name(old_name, new_name):
+```
+### Syntax Error
+*   Error #1: `SyntaxError: invalid syntax`
+*   Erroneous code:
+```py
+def first_name(old_name, new_name)
+```
+*   **Cause**:   Missing a colon in the end.
+
+***Instructor note:*** Look for simular errors in `for ... :` and `if ...:` and `while ... :` lines :) Or any block indent required lines (when next line will be with block indent) They always go together - `:` and following block indent.
+
+## Case 6. Tricky f-strings
+*   Correct code: 
+```py
+print(f'Number of {legs:b}')
+```
+### Syntax Error
+*   Error #1: `SyntaxError: invalid syntax`
+*   Erroneous code:
+```py
+print(f'Number of {legs:b')
+```
+*   **Cause**:   Did not end f-string argument with a ‘}’
+
+
+
+## Case 6. String concatenation
+*   Correct code: 
+```py
+num = 6
+print("I would like " + str(num) + " tacos please.")
+```
+### Type Error
+*   Error #1: `TypeError`
+*   Erroneous code:
+```py
+num = 6
+print("I would like " + num + " tacos please.")
+```
+*   **Cause**:    You can only concatenate a string, not an interger type with a string. 
+
+
+## Case 7. Variables inside the functions
+*   Correct code: 
+```py
+def vol(height):
+  if height == 3:
+    lenght = 2
+    return lenght
+  else:
+    lenght = 4
+    return lenght
+
+if __name__ == "__main__":
+  provided_height = input()
+  num = vol(provided_height)
+  print(num)
+```
+### Name Error
+*   Error #1: `name 'lenght' is not definded.`
+*   Erroneous code:
+```py
+def vol(lenght):
+  if height == 3:
+    lenght = 2
+    return lenght
+  else:
+    lenght = 4
+    return lenght
+
+if __name__ == "__main__":
+  provided_height = input()
+  num = vol(provided_height)
+  print(num)
+```
+*   **Cause**:    I should use the NAME which appeared in the IF branch as Argument Name.
+
+
+## Case 8. Float or intreger conversion?
+*   Correct code: 
+```py
+current_year = '1792'
+current_year = int(current_year)
+print(current_year)
+```
+or 
+```py
+current_year = '1792.99'
+current_year = float(current_year)
+print(current_year)
+```
+### ValueError
+*   Error #1: `ValueError: invalid literal for int() with base 10: '1792.99'`
+*   Erroneous code:
+```py
+current_year = '1792.99'
+current_year = int(current_year)
+print(current_year)
+```
+*   **Cause**:   If you do want to pass a string representation of a float to an int,  you need to convert to a float first, then to an integer.
 
-TBA
 
 ---
 
 #### Acknowledgement
 
 Developed by Yekaterina Kharitonova with assistance from students and course mentors.
+Students that provided examples above:
+- Ruopu Bai
+- Hanwen Zhang
+- Natalya Rodriguez
+- James McNeice
+- Francisco Silva
+- Mu Niu
+
 {: .fs-2 }