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 codefor (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.