In Algorithm Design Lab, accepting the number of disks from the user is an important first step in implementing the Tower of Hanoi problem. The Tower of Hanoi is a classical recursive problem used to understand recursion, algorithm design, problem decomposition, and computational complexity. The problem consists of three rods and a number of disks of different sizes. Initially, all disks are placed on the first rod in decreasing order of size, with the largest disk at the bottom and the smallest disk at the top. The objective is to move all disks from the source rod to the destination rod using the auxiliary rod while following certain rules. The first requirement of the algorithm is to obtain the number of disks from the user. The number of disks is generally represented by the variable `n`. The program asks the user to enter an integer value, which represents how many disks are to be considered for the Tower of Hanoi problem. The input value determines the size of the problem and directly affects the number of recursive operations required. A simple C++ implementation for accepting the number of disks is: ```cpp #include using namespace std; int main() { int n; cout << "Enter the number of disks: "; cin >> n; cout << "Number of disks entered: " << n << endl; return 0; } ``` In this program, `#include ` provides the input and output facilities required for communicating with the user. The statement `using namespace std;` allows standard library objects such as `cout` and `cin` to be used without writing `std::` repeatedly. Inside the `main()` function, an integer variable `n` is declared. The statement `cout << "Enter the number of disks: ";` displays a message requesting the user to provide the number of disks. The `cin >> n;` statement accepts the value entered by the user and stores it in the variable `n`. For example, if the user enters: ```text Enter the number of disks: 3 ``` the value `3` is stored in `n`. This value can then be passed to a recursive Tower of Hanoi function to calculate and display the required disk movements. The complete algorithm can be extended after accepting the input. The basic recursive idea is that to move `n` disks from one rod to another, the first `n-1` disks must be moved from the source rod to the auxiliary rod. The largest disk can then be moved from the source rod to the destination rod. Finally, the `n-1` disks placed on the auxiliary rod are moved to the destination rod. This process continues recursively until only one disk remains. The recursive function can be written as: ```cpp