C++ Program to Find Factorial

Source Code

``````#include <iostream>

using namespace std;

int main()
{
int n; // Declare a variable to hold the number
int fact = 1; // Declare a variable to hold the factorial and initialize it to 1

cout << "Enter a number: "; // Prompt the user to enter the number
cin >> n; // Read the number from the standard input stream

// Calculate the factorial of the number
for (int i = 1; i <= n; i++)
fact *= i;

cout << "The factorial of " << n << " is: " << fact << endl; // Print the factorial

return 0;
}
``````

Code Explanation

This program declares a variable `n` of type `int` to hold the number entered by the user, and a variable `fact` of type `int` to hold the factorial of the number. It then uses the `cout` object to print a prompt asking the user to enter the number, and the `cin` object to read the number from the standard input stream.

To calculate the factorial of the number, the program uses a `for` loop to iterate over the range `[1, n]` and multiply each number by the factorial. The loop variable `i` is initialized to 1, and the loop continues as long as `i` is less than or equal to `n`. The loop variable is incremented by 1 on each iteration.

Finally, the program uses the `cout` object to print the value of `fact`, which is the factorial of the number.

What is Loop in C++?

In C++, a loop is a control flow statement that allows you to execute a block of code repeatedly. There are several types of loops in C++, including:

• `for` loops: These loops execute a block of code a specified number of times. They have a loop variable that is initialized, tested, and updated on each iteration.
• `while` loops: These loops execute a block of code as long as a specified condition is true. The condition is tested at the beginning of each iteration.
• `do-while` loops: These loops are similar to `while` loops, but the condition is tested at the end of each iteration. This means that the block of code will be executed at least once.

Here is an example of a `for` loop in C++:

```Copy code```for (int i = 1; i <= 10; i++)
{
cout << i << endl;
}
``````

This loop will print the numbers 1 through 10 on separate lines. The loop variable `i` is initialized to 1, and the loop continues as long as `i` is less than or equal to 10. The loop variable is incremented by 1 on each iteration.

This loop will print the numbers 1 through 10 on separate lines. The loop variable `i` is initialized to 1, and the loop continues as long as `i` is less than or equal to 10. The loop variable is incremented by 1 on each iteration.