Chapter 7: Problem 3
A certain CS professor gives 100 -point exams that are graded on the scale \(90-100: \mathrm{A}, 80-89: \mathrm{B}, 70-79: \mathrm{C}, 60-69: \mathrm{D},<60: \mathrm{F} .\) Write a program that ac cepts an exam score as input and uses a decision structure to calculate the corresponding grade.
Short Answer
Expert verified
Input the score, check its range with if-elif-else statements, and output the grade.
Step by step solution
01
Understand the Problem
We are asked to create a program that accepts a score (a number between 0 and 100) and outputs a grade based on provided ranges for grades A through F.
02
Define the Grade Ranges
The grade ranges are defined as follows:
- A: 90 to 100
- B: 80 to 89
- C: 70 to 79
- D: 60 to 69
- F: Less than 60.
03
Choose the Programming Language
Before writing the code, select a programming language. For this example, let's use Python because of its simplicity in handling conditional statements.
04
Write the Program with Conditional Statements
Use 'if-elif-else' statements to determine the grade. Here's one way to do it in Python:
```python
score = int(input("Enter the exam score: "))
if 90 <= score <= 100:
grade = 'A'
elif 80 <= score <= 89:
grade = 'B'
elif 70 <= score <= 79:
grade = 'C'
elif 60 <= score <= 69:
grade = 'D'
else:
grade = 'F'
print(f"The grade is {grade}.")
```
05
Break Down the Code
In the code above:
- We ask the user to input an exam score and convert it to an integer.
- We use 'if' statements to check if the score falls within a particular range and assign the corresponding grade.
- Finally, we print out the grade.
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Conditional Statements
In Python programming, conditional statements allow us to execute certain sections of our code based on specific conditions. They form the backbone of decision-making in programming, enabling our programs to behave differently in different situations based on the input or past situations.
The primary conditional statement in Python is the `if` statement. It checks a condition and executes the code block within it if the condition is `True`. To check multiple conditions, you can use `elif` (short for "else if") for additional checks. Finally, we use `else` to specify a block of code that executes if none of the previous conditions were `True`. This structure helps in evaluating various situations to guide the program toward a desired outcome.
For example, in our grading system program, we use conditional statements to determine the grade a student receives based on their score. If a student's score meets a specified condition such as `90 <= score <= 100`, the program assigns an 'A'. The use of `elif` provides additional conditions with different actions, making decision-making structured and clear.
The primary conditional statement in Python is the `if` statement. It checks a condition and executes the code block within it if the condition is `True`. To check multiple conditions, you can use `elif` (short for "else if") for additional checks. Finally, we use `else` to specify a block of code that executes if none of the previous conditions were `True`. This structure helps in evaluating various situations to guide the program toward a desired outcome.
For example, in our grading system program, we use conditional statements to determine the grade a student receives based on their score. If a student's score meets a specified condition such as `90 <= score <= 100`, the program assigns an 'A'. The use of `elif` provides additional conditions with different actions, making decision-making structured and clear.
Grading System
A grading system automates the process of determining grades based on given scores. It uses predefined rules or criteria to produce a grade reflecting a student's performance. In the case of our exercise, the system is simple and straightforward.
Here is the grading scale:
Here is the grading scale:
- A: 90 to 100
- B: 80 to 89
- C: 70 to 79
- D: 60 to 69
- F: Less than 60
Decision Structures
Decision structures in programming enable a program to make choices based on conditions. These structures are pivotal in adapting the program's flow according to the data encountered. In Python, the primary components of a decision structure include `if`, `elif`, and `else` blocks.
Decision structures can be visualized like flow charts: they start at a decision node (condition) and branch out into different paths depending on whether the condition is met or not. This is crucial for real-world applications like the grading system where exact paths of logic ensure accurate and efficient outcomes.
Each branch of our code handles a specific range of exam scores by executing a distinct block of code. It matches a student's score to a grade that accurately represents their performance. This systematic approach is pivotal for producing clear and defined results in any rule-based or logic-driven programming task. By leveraging decision structures, programmers can build robust and reliable applications that adjust their behavior dynamically.
Decision structures can be visualized like flow charts: they start at a decision node (condition) and branch out into different paths depending on whether the condition is met or not. This is crucial for real-world applications like the grading system where exact paths of logic ensure accurate and efficient outcomes.
Each branch of our code handles a specific range of exam scores by executing a distinct block of code. It matches a student's score to a grade that accurately represents their performance. This systematic approach is pivotal for producing clear and defined results in any rule-based or logic-driven programming task. By leveraging decision structures, programmers can build robust and reliable applications that adjust their behavior dynamically.
