C++ Program to find factorial of Number
Find factorial of a Number in C++
Program to find factorial of Number in C++
What is a Factorial of a number ‘n’?
The factorial of a number ‘n’ is the product of all number from 1 upto the number ‘n’
it is denoted by n!.
For example:
4! = 4*3*2*1 = 24
6! = 6*5*4*3*2*1 = 720
Source code:
#include<iostream>
/* iostream provides basic
input and output services for C++ programs */
using namespace std;
int main()
// Th execution of program start with the main function
{
int num,factorial=1;
//Variable Declarations specify the type followed by the name
//Initialization is the process of assign the value to a variable
cout<<" Enter Number To Find Its Factorial: ";
// cout is used to display the same statement in the output.
cin>>num;
// cin is used to enter the value by the user.
if (num < 0)
/* The if/else statement executes a block
of code if a specified condition is true.
If the condition is false, another block
of code can be executed*/
cout << "Error! Factorial of a negative number doesn't exist.";
else {
for (int a=1;a<=num;a++)
// for loop
{
factorial=factorial*a;
}
cout<<"Factorial of " <<num <<" is :"<<factorial<<endl;
return 0;
}
}
In this program, we take a positive integer from the user and compute the factorial using for loop. We print an error message if the user enters a negative number.
When the user enters a positive integer for loop is executed and computes the factorial. The value of a is initially 1.
The program runs until the statement a <= num becomes false.
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