Day 8: Visualizing the Call Stack: How Recursion Actually Works

We've all heard the term "Stack Overflow," but today I visualized what it actually means.

When a function calls itself (Recursion), it doesn't just "loop." The computer actually pauses the current function, packages up all the variables, and pushes a new Stack Frame onto memory.

• Frame 1: n = 3 (Paused)
• Frame 2: n = 2 (Paused)
• Frame 3: n = 1 (Running)

If you recurse too deep without stopping, you run out of Stack memory. Boom. Stack Overflow.

The Code

This program prints the memory address of the local variable n during each recursive call. You will see the addresses moving down in memory, proving that each call creates a new, distinct stack frame.

// Day 8: Visualizing Stack Frames

#include <stdio.h>

void recursive_print(int n) {
    // Base case: Stop when n hits 0
    if (n == 0) {
        printf("Base case reached. Popping stack now...\n");
        return;
    }

    // Print the address of 'n' to see the stack grow
    // Notice the addresses get smaller (Stack grows DOWN)
    printf("Frame %d | Address of n: %p\n", n, (void*)&n);

    // Recursive step: Call itself with n-1
    recursive_print(n - 1);

    printf("Returning from Frame %d\n", n);
}

int main() {
    recursive_print(3);
    return 0;
}

📂 View the source code on GitHub:https://github.com/Ujjawal0711/30-Days