Write a C++ program to read an integer n and prints the factorial of n

Assignment 10

Write a C++ program to read an integer n and prints the factorial of n.

Program Code with explanation:

1.    #include <iostream>

2.    using namespace std;

3.    int main()

4.    {

5.          int n, i, fact = 1;

6.          cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

7.          cout << " \t Accept number n to find Factorial \n ";

8.          cout << " * * * * * * * * * * * * * * * * * * * * * * *  * * * * * * \n \t";

9.          cin >> n;

10.       for ( i = 1 ; i <= n ; i ++ )

11.       {

12.                   fact = fact  *  i;

13.       }

14.       cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

15.       cout << " \t Factorial of " << n << " is " << fact << endl;

16.       cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

17.       return 0;

18. }

Explanation of Code:

Line No. 1 and 2: include the Library file and stander input – output functions.

Line No. 3: main function header.

Line No. 4 and 18: Begin and end of main function respectively.

Line No. 5: Declare the three integer variables.

Line No. 7 and 9: Accept number n from user to find Factorial.

Line No. 10 to 13: for loop iteration form 1 to n.

            We declare the variable fact with initialization value 1. Calculate the factorial in variable fact.  

            For example,

Factorial of 5 = 1 * 2 * 3 * 4 * 5.

So in for loop, we use the variable i as a counter variable move the value from 1 to n and calculate the factorial using expression fact = fact  *  i;

Line No. 15: Display the factorial of number n.

Line No. 17: return statement appropriate with main function return data type.

Program Code for run:

#include <iostream>

using namespace std;

int main()

{

    int n, i, fact = 1;

    cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

    cout << " \t Accept number n to find Factorial \n ";

    cout << " * * * * * * * * * * * * * * * * * * * * * * *  * * * * * * \n \t";

    cin >> n;

   

    for ( i = 1 ; i <= n ; i ++ )

    {

        fact = fact  *  i;

    }

    cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

    cout << " \t Factorial of " << n << " is " << fact << endl;

    cout << " * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \n";

    return 0;

}

 

Output of Program:

          * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
                 Accept number n to find Factorial
          * * * * * * * * * * * * * * * * * * * * * * *  * * * * * *
                3
         * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
                 Factorial of 3 is 6
         * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *