Execution Flow: Quiz I in C++ - Time Complexity: O(1)

Quiz: What would this code produce if we were to copy-paste it in a code editor and run it?

void welcomeUser() {
	cout << "Hey coder!" << endl;
}
void mainFunction() {
	cout << "Welcome back!" << endl;
	welcomeUser();
}

Options:

A: It would print:
```
Hey coder!
Welcome back!
```
B: It would print:
```
Welcome back!
```
C: It would produce errors
D: It would print:
```
Welcome back!
Hey coder!
```

Important Note:

Do not use an actual code editor to get the answer! It would defy the whole purpose of the quiz!

Instructions:

Pick your answer and assign variable answer in the code editor with that answer.

For example, if you think the answer to the quiz is B, write answer = "B" in the code editor and press Validate Solution!.

Understanding the Problem

The core challenge of this problem is to understand the flow of execution in a C++ program. Specifically, we need to determine the order in which the functions are called and the output they produce.

This problem is significant because understanding the flow of execution is fundamental to debugging and writing correct programs. Misunderstanding the order of function calls can lead to logical errors in more complex programs.

Potential pitfalls include assuming the order of function calls incorrectly or misunderstanding the scope and lifetime of variables and functions.

Approach

To solve this problem, we need to carefully trace the execution of the code:

Identify the entry point of the program.
Follow the sequence of function calls.
Determine the output produced by each function call.

Let's break down the code step-by-step:

void welcomeUser() {
	cout << "Hey coder!" << endl;
}
void mainFunction() {
	cout << "Welcome back!" << endl;
	welcomeUser();
}

In this code, the function welcomeUser() prints "Hey coder!" and the function mainFunction() prints "Welcome back!" and then calls welcomeUser().

Algorithm

Here is a step-by-step breakdown of the algorithm:

When mainFunction() is called, it prints "Welcome back!".
Then, mainFunction() calls welcomeUser().
welcomeUser() prints "Hey coder!".

Therefore, the output will be:

Welcome back!
Hey coder!

Code Implementation

#include <iostream>
using namespace std;

void welcomeUser() {
    // This function prints "Hey coder!"
    cout << "Hey coder!" << endl;
}

void mainFunction() {
    // This function prints "Welcome back!" and then calls welcomeUser()
    cout << "Welcome back!" << endl;
    welcomeUser();
}

int main() {
    // Entry point of the program
    mainFunction();
    return 0;
}

Complexity Analysis

The time complexity of this program is O(1) because the number of operations does not depend on any input size. The space complexity is also O(1) as no additional space is required beyond a few variables.

Edge Cases

There are no significant edge cases for this problem as it involves a straightforward sequence of function calls and print statements.

Testing

To test this solution, you can run the program and verify that the output matches the expected result:

Welcome back!
Hey coder!

Ensure that the functions are called in the correct order and produce the expected output.

Thinking and Problem-Solving Tips

When approaching similar problems, consider the following tips:

Carefully trace the flow of execution, especially the order of function calls.
Understand the scope and lifetime of variables and functions.
Practice writing and debugging small programs to build a strong foundation in understanding execution flow.

Conclusion

In this blog post, we explored the execution flow of a simple C++ program. We discussed the importance of understanding function calls and the order of execution. By carefully tracing the code, we determined the correct output and provided a detailed explanation of the algorithm and its implementation.

Understanding execution flow is crucial for writing correct and efficient programs. We encourage readers to practice similar problems and deepen their understanding of C++ programming.

Additional Resources

For further reading and practice, consider the following resources: