Improving code readability - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested if-else with clear indentation

What is the output of this C code snippet?

C

#include <stdio.h>

int main() {
    int x = 5;
    if (x > 3) {
        if (x < 10) {
            printf("Inside range\n");
        } else {
            printf("Too large\n");
        }
    } else {
        printf("Too small\n");
    }
    return 0;
}

A Inside range

B Too large

C Too small

D No output

💡 Hint

Check the conditions carefully and follow the indentation to see which block runs.

The variable x is 5, which is greater than 3 and less than 10, so the first inner if condition is true. The program prints "Inside range".

🧠 Conceptual

intermediate

Best practice for variable naming

Which variable name is the most readable and follows good naming conventions in C?

A int numberOfStudents;

B int x;

C int n;

D int a1;

💡 Hint

Think about names that clearly describe what the variable holds.

Variable names should be descriptive and meaningful. 'numberOfStudents' clearly tells what the variable represents, improving code readability.

🔧 Debug

advanced

Identify the readability issue in this code

What is the main readability problem in this C code snippet?

C

int main(){int a=10;int b=20;if(a>b){printf("A is bigger\n");}else{printf("B is bigger\n");}return 0;}

A Missing semicolons

B Incorrect use of printf

C Lack of spaces and indentation makes it hard to read

D Variables are not declared

💡 Hint

Look at how the code is spaced and arranged.

The code lacks proper spacing and indentation, making it difficult to follow. Adding spaces and new lines improves readability.

📝 Syntax

advanced

Which option causes a syntax error?

Which of the following C code snippets will cause a syntax error?

A if (x > 0) printf("Positive\n");

B if x > 0 { printf("Positive\n"); }

C

if (x > 0)
    printf("Positive\n");

D if (x > 0) { printf("Positive\n"); }

💡 Hint

Remember the syntax rules for if statements in C.

Option B is missing parentheses around the condition and uses braces incorrectly, causing a syntax error.

🚀 Application

expert

How many items are printed by this loop?

Consider this C code. How many lines will it print?

C

#include <stdio.h>

int main() {
    for (int i = 0; i < 10; i++) {
        if (i % 2 == 0) {
            printf("%d\n", i);
        }
    }
    return 0;
}

A 0

B 10

C 9

D 5

💡 Hint

Count how many numbers from 0 to 9 are even.

The loop prints numbers from 0 to 9 that are even. These are 0, 2, 4, 6, 8 — a total of 5 lines.

Practice

1. Why is it important to use meaningful variable names in C code?

easy

A. It makes the program run faster.

B. It makes the code easier to understand for others and yourself.

C. It reduces the size of the compiled program.

D. It allows the compiler to optimize memory usage.

Solution

1. Step 1: Understand variable naming purpose

   Meaningful names describe what the variable holds, making code clearer.

2. Step 2: Consider code readability impact

   Clear names help anyone reading the code understand its purpose quickly.

3. Final Answer:

   It makes the code easier to understand for others and yourself. -> Option B

4. Quick Check:

   Meaningful names improve readability [OK]

Hint: Choose names that describe purpose clearly [OK]

Common Mistakes:

• Using single letters without context
• Using vague names like temp or data
• Ignoring naming conventions

2. Which of the following is the correct way to format an if statement in C for better readability?

easy

A. if (x > 0) { printf("Positive"); }

B. if(x>0){printf("Positive");}

C. if(x > 0)printf("Positive");

D. if ( x>0 ) {printf("Positive");}

Solution

1. Step 1: Check spacing around operators and keywords

   if (x > 0) { printf("Positive"); } uses spaces after if, around operators, and braces properly.

2. Step 2: Check consistent brace placement

   if (x > 0) { printf("Positive"); } places braces with spaces, improving readability.

3. Final Answer:

   if (x > 0) { printf("Positive"); } -> Option A

4. Quick Check:

   Proper spacing and braces improve readability [OK]

Hint: Use spaces around operators and braces consistently [OK]

Common Mistakes:

• Skipping spaces after keywords
• Putting braces on the same line without spaces
• Omitting braces for single statements

3. What is the output of the following C code snippet?

int main() {
    int a = 5, b = 10;
    int sum = a + b;
    printf("Sum is %d\n", sum);
    return 0;
}

medium

A. Sum is 15

B. Sum is 510

C. Sum is a + b

D. Compilation error

Solution

1. Step 1: Understand variable initialization and addition

   Variables a and b are assigned 5 and 10, sum is their addition (5 + 10 = 15).

2. Step 2: Analyze printf output

   printf prints "Sum is " followed by sum's value, which is 15.

3. Final Answer:

   Sum is 15 -> Option A

4. Quick Check:

   5 + 10 = 15 output [OK]

Hint: Add variables before printing to get correct sum [OK]

Common Mistakes:

• Concatenating integers as strings
• Forgetting to add variables
• Syntax errors in printf format

4. Identify the readability issue in this C code and select the best fix:

int main(){int x=10;int y=20;if(x>y){printf("x is greater\n");}else{printf("y is greater\n");}return 0;}

medium

A. Use goto statements for flow control.

B. Remove all spaces to make it compact.

C. Change variable names to single letters.

D. Add spaces and line breaks for clarity.

Solution

1. Step 1: Analyze current formatting

   Code is cramped with no spaces or line breaks, making it hard to read.

2. Step 2: Suggest formatting improvements

   Adding spaces and line breaks separates statements and improves readability.

3. Final Answer:

   Add spaces and line breaks for clarity. -> Option D

4. Quick Check:

   Proper formatting improves readability [OK]

Hint: Use indentation and spaces to separate code blocks [OK]

Common Mistakes:

• Ignoring formatting leads to hard-to-read code
• Using goto increases complexity
• Making names less descriptive

5. You have a function that calculates the area of a rectangle:

float area(float w, float h){return w*h;}

How can you improve this code's readability for a team project?

hard

A. Use single-letter variable names to shorten code.

B. Remove the return statement to simplify.

C. Add descriptive comments and use meaningful parameter names.

D. Write the function in one line without spaces.

Solution

1. Step 1: Review current function

   Function uses short parameter names and no comments, which may confuse others.

2. Step 2: Suggest improvements

   Using descriptive names like width and height and adding comments clarifies purpose.

3. Final Answer:

   Add descriptive comments and use meaningful parameter names. -> Option C

4. Quick Check:

   Comments and clear names improve teamwork [OK]

Hint: Explain purpose with comments and clear names [OK]

Common Mistakes:

• Using vague parameter names
• Skipping comments
• Making code too compact