Program to Calculate Factorial of n Number

This article describes how to calculate factorial of n number in C/C++?. Let us describes about factorial number.

What is Factorial!
The factorial means to multiply a series of descending natural numbers. Its symbol is! And pronounced n factorial. But some people even say “4 shriek” or “4 bang”
In mathematics the factorial of a natural number n is the product of the positive integers less than or equal to n. It is written as n!

Examples:

0! = 1
1! = 1
2! = 2×1 = 2
3! = 3×2×1 = 6
4! = 4×3×2×1 = 24
5! = 5×4×3×2×1 = 120

Where is Factorial Used?
Factorials are used in many areas of mathematics. It is used particularly in Combinations and Permutations.

What About Decimals?
Can we have factorials for numbers like 0.6 or -5.217?
Yes we can! But you need to get into a subject called the “Gamma Function”.


Program to Calculate Factorial of n Number (using for loop)

#include
#include
int main(){
clrscr();
long double n,i,fact=1;

cout<<” ” This program will claculate Factorial of n number (using For loop). “”<<endl<<endl;

xx:
cout<<“How many numbers ?. Give a integer number.”<<endl;
cin>>n;

if (n<0) {
cout<<“Negative number not allow, Please give integer number.”<<endl;
goto xx;
}

for(i=1;i<=n;i++)
fact=fact*i;

cout<<endl;
cout<<“Factorial of “<<n<<” is : ” <<fact;

getch();
}

Program to Calculate Factorial of n Number (using do-while loop)
#include
#include
int main(){
clrscr();
long double  n,i,fact=1;

cout<<”  ” This program will show the Factorial of n numer (usin do-while loop). “”<<endl<<endl;

xx:
cout<<“Give how many numbers ?. Give a integer number.”<<endl;
cin>>n;

if (n<0) {
cout<<“Negative number is not allow, Please give integer number.”<<endl;
goto xx;
}

i=1;
do {
fact=fact*i;
i++;
}

while(i<=n);

cout<<endl;
cout<<“Factorial of “<<n<<” is : ” <<fact;

getch();
}

Program to Calculate Factorial of n Number (using while loop)
#include
#include
int main(){
clrscr();
long double n,i,fact=1;

cout<<” ” This program will show the Factorial of n number (using while loop).””<<endl<<endl;

xx:
cout<<“How many numbers ?.Give a integer number. “<<endl;
cin>>n;

if (n<0) {
cout<<“Negative number is not allow, Please give integer number.”<<endl;
goto xx;
}

i=1;
while(i<=n){
fact=fact*i;
i++;
}

cout<<endl;
cout<<“Factorial of “<<n<<” is : ” <<fact;

getch();
}

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