Question

Show \(C++\) code for defining a variable ptr that is a pointer to a constant int.

Short answer

Answer: To define a pointer to a constant integer in C++, first create a constant integer variable using the `const` keyword and assign a value to it, such as `const int number = 42;`. Then, define a pointer by specifying the data type as `const int*`, followed by the pointer variable's name, and using the address-of operator (&) to assign the memory address of the constant integer variable to the pointer, like this: `const int* ptr = &number`.

Step-by-step solution

Define a Constant Int Variable

Firstly, define a constant integer variable. To do this, use the const keyword followed by the int data type and provide it with a value. In our example, let's assign the value 42 to our constant int variable. ```cpp const int number = 42; ```

Define a Pointer to the Constant Int Variable

Now we will define a pointer to the constant integer. A pointer is a variable that stores the memory address of another variable. To create a pointer, use the data type of the variable the pointer will point to (in this case, a constant int), followed by an asterisk (*) before the pointer variable's name. Then use the & (address-of operator) followed by the constant int variable's name to assign the memory address of the consant int to the pointer variable. ```cpp const int* ptr = &number ```

Final C++ Code

Combining both the steps, here's the complete C++ code: ```cpp #include int main() { const int number = 42; // Step 1: Define a constant int variable const int* ptr = &number // Step 2: Define a pointer to the constant int variable // Print the constant int value using the pointer std::cout << "The pointed value is: " << *ptr << std::endl; return 0; } ```