Pre-DSA Essentials: Pass By Value , Pass By Reference and Arrays in C++

Hello 🌟, Welcome back to my exciting journey of learning Data Structures and Algorithms (DSA) using C++. In today's session, which I like to call "Pre-DSA Part 2," we'll be exploring some more fundamental concepts that will lay a solid foundation for my DSA adventure.

Pass by Value Using Pointers: Simple and Straightforward

Hey not more technical! Passing by value using pointers is just what it sounds like - we're passing a copy of the value to a function. Let's break it down.

void modifyValue(int x) {
    x = x * 2;
}

int main() {
    int num = 5;
    modifyValue(num);
    // num remains 5
    return 0;
}

In this example, num remains 5 because the function modifyValue receives a copy of num, and any changes inside the function don't affect the original variable.

Pass by Reference Using Pointers: The Power to Change

Now, let's kick it up a notch! Pass by reference using pointers allows us to pass the memory address of a variable to a function, giving that function the power to modify the original variable.

void modifyValue(int* ptr) {
    *ptr = *ptr * 2;
}

int main() {
    int num = 5;
    modifyValue(&num);
    // num is now 10
    return 0;
}

In this example, num becomes 10 because the function modifyValue receives a pointer to num, and any changes to the memory location pointed to by ptr directly affect num.

Arrays: Managing Variables Like a Pro

Imagine you have to manage the scores of 100 students in your class. Each student has a unique score, and you need a way to keep track of all these numbers efficiently. Without the right tool, this could be a daunting task.

But fear not, for we have a powerful tool at our disposal: Arrays!

Arrays in C++ are like magical containers that allow us to store and manage multiple values of the same type under a single variable name. They bring order to chaos, making it possible to handle a vast amount of data with ease. Let's grasp the basics.

int scores[100]; // Declare an integer array with space for 5 elements
scores[0] = 95; // Assign values to array elements
scores[1] = 87;
scores[2] = 72;
scores[3] = 68;
scores[4] = 91;
.
.
.
scores[100] = 78;

Arrays are zero-indexed in C++, meaning the first element is at index 0, the second at 1, and so on. To access array elements, you use square brackets.

int secondScore = scores[4]; // Access the second element (91)

Arrays are essential for many data structures, so mastering them is a key step in our journey toward DSA expertise!

Conclusion

In this session, we've covered more ground in our Pre-DSA exploration. We've learned the difference between pass by value and pass by reference using pointers, giving us the tools to control variable modification within functions. Additionally, we've touched on arrays, which are the fundamental data structure for storing collections of data.

Our journey is just beginning, and there's so much more to learn about data structures and algorithms using C++. Stay tuned for our next session, where we'll delve deeper into this fascinating world. Happy coding, and keep the tech spirit alive! 🚀✨