Question

Write a program that translares a letter grade into a number grade. Letter grades are \(A, B, C, D\), and \(F\), possibly followed by \(+\) or \(-.\) Their numeric values are \(4,3,2,1\), and 0. There is no \(\mathrm{F}+\) or \(\mathrm{F}-. \mathrm{A}+\) increases the numeric value by \(0.3\), a \(-\) decreases it by \(0.3 .\) However, an A+ has value \(4.0\). Enter a Tetter grade: \(\mathbb{B}\) - The nuneric value is \(2.7\).

Short answer

The numeric value for grade 'B-' is 2.7.

Step-by-step solution

Understanding the Problem

We need a program that converts a letter grade into a numeric grade based on specific rules. The letter grade can be A, B, C, D, or F and might have a '+' or '-' sign accompanying it. The numeric values for each letter grade are A = 4, B = 3, C = 2, D = 1, F = 0. A '+' increases the value by 0.3, and a '-' decreases it by 0.3, except for A+, which remains 4.0.

Define Numeric Values for Grades

We first need to associate each letter grade with its base numeric value. We set up a dictionary: `{'A': 4, 'B': 3, 'C': 2, 'D': 1, 'F': 0}` for easy lookup.

Handling Modifiers (+/-)

If the grade has a '+' or '-', we adjust the base numeric value. Add 0.3 for '+', subtract 0.3 for '-', except A+ should be maxed at 4.0.

Write the Program

Here's a possible implementation in Python: ```python # Define a function to translate letter grade to numeric grade def translate_letter_grade(letter_grade): # Dictionary for base letter grade values base_values = {'A': 4, 'B': 3, 'C': 2, 'D': 1, 'F': 0} # Extract the main grade and any modifier main_grade = letter_grade[0] modifier = letter_grade[1:] if len(letter_grade) > 1 else '' # Get the base numeric value numeric_value = base_values[main_grade] # Adjust the numeric value based on the modifier if main_grade != 'F': if modifier == '+': numeric_value += 0.3 elif modifier == '-': numeric_value -= 0.3 # Ensure A+ does not exceed 4.0 if main_grade == 'A' and modifier == '+': numeric_value = 4.0 return numeric_value # Test the function letter_grade = 'B-' numeric_value = translate_letter_grade(letter_grade) print(f'The numeric value is {numeric_value}.') ```

Verify the Solution

After implementing the code, run it with the letter grade input 'B-' to see if it correctly outputs the numeric value 2.7, verifying that the program works as intended.

Key concepts

Grade Conversion

Grade conversion in programming involves transforming a letter grade, such as 'A' or 'B+', into a numeric representation that can be more universally understood or manipulated in calculations. In this context, we are tasked with converting letter grades into their numeric equivalents using Python programming. This is an essential skill in educational software development, where numeric scores often need to be computed from qualitative grades.
To achieve accurate grade conversion, a standard mapping system is used:

• 'A' maps to 4
• 'B' maps to 3
• 'C' maps to 2
• 'D' maps to 1
• 'F' maps to 0

Additionally, a modifier like '+' increases the numeric value by 0.3, while '-' decreases it by 0.3. The special case is 'A+', which totals out at 4.0 even though it technically deserves 4.3. Understanding this mapping is crucial for understanding conditional logic in programming that deals with educational data.

Algorithm Design

Algorithm design is the process of devising a step-by-step method to solve a problem. For our grade conversion program, the algorithm involves several clear steps:

• Extract the main grade letter and check if there is a modifier (e.g., '+', '-').
• Refer to an established dictionary to find the base numeric value for the grade letter.
• Apply any modifiers by adding or subtracting 0.3 from the base value, remembering that 'A+' does not exceed 4.0.

Creating a robust algorithm involves more than just writing code. It requires

• Thinking through all possible inputs
• Consideration of edge cases (such as no '+' or '-' for 'F')

By breaking down the problem and systematically implementing solutions in code, programmers can solve similar tasks more efficiently and reduce errors.

Conditional Statements

Conditional statements in Python are used to make decisions within a program. They allow execution of certain parts of code depending on whether a condition is true or false. In the context of our grade conversion program, these statements help adjust the numeric value based on modifiers.

In the provided Python script, conditional statements are employed to:

• Check if the main grade letter is 'F' to ensure no modifications occur with a '+' or '-'.
• Decide if a '+' should add 0.3 or a '-' should subtract 0.3 from the numeric score.
• Ensure that 'A+' always results in exactly 4.0 by overriding any alteration which would push it over this value.

These statements, often framed with `if`, `elif`, and `else`, are the backbone of decision-making in algorithmic processes. Proper use of conditional statements ensures that our application can handle all conceivable inputs gracefully and output the correct numeric conversions.