How to write a factorial program and prime number prog

Md Nayeem

8y1.9k

How to write a factorial program and prime number program using array in c programming?

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Mohan Arumugam8y ago
Factorial Program
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace factorial
{
   class  fact
   {
    static void main(string[] args)
     {
       int i, num, fact;
       Console.WriteLine("Enter the No");
       num = int.Parse(Console.ReadLine());
       fact = num;
       for(i = num-1; i>=1; i--)
       {
         fact = fact * i;
       }
       Console.WriteLine("factorial of given number is : "  +fact);
       Console.ReadLine();
     }
   }
}
2.Prime Number Program
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace PrimeNumber
{
   class prime
   {
      int []  num = new int[5];
    int i,j;
    bool isprime,noprime = true;
    public findprime()
    {
  Console.WriteLine("Please enter 5 numbers: ");
  for(i = 0; i < 5; i++)
  num[i] = Int16.Parse(Console.ReadLine()); /* add Numbers to the Array*/
  for(i = 0; i < 5; i++)
  {
  isprime = true; /* initialize Current number as prime Number is "true"*/
  for (j = 2; j <= (num[i] / 2); j++)
{
if (num[i] % j == 0)
{
isprime = false;
break;
}
}
if (isprime) /*if no Remainder "0" Display current Number as Prime Number*/
{
noprime = false;
Console.WriteLine(num[i] + " is a Prime Number");
}
}
if (noprime)
Console.WriteLine("There is no a Prime number in the list");
    }
   }
}
Mahesh Verma8y ago
Hi Md Nayeem,

According to me, you want to print all prime numbers and factorial of each number in an array.
So, we created two functions here, so, that you can easily find that element:
#include
#include

void factorial (int);
void prime(int);

void main()
{
   int arr[10],i;
   clrscr();
   cout<<"Enter elements of an array :- ";
   for(i=0;i<=9;i++)
   cin>>arr[i];

   for(i=0;i<=9;i++)
   {
       factorial(arr[i]);     //passing each element to find factorial
       prime(arr[i]);
   }

   getch();
}

void factorial(int n)
{
     int fact=1;
     while(n>1)
    {
        fact*=n;
        n--;
     }
    cout<<"Factorial of  "<" is"<
}

void prime(int n)
{
     int i=1, factor=0;
     while(i<=n)
     {
          if(n%i==0)
             factor++;
          i++;
      }
      if(factor==2)
      cout<<"\n"<" is prime";
}
Rushi Mehta8y ago
Below is prime number programme
#include

using std::cin;
using std::cout;
using std::endl;

int main()
{
    const int arraysize = 1000;
        int x, a[arraysize], b;

    for (x=0; x < arraysize; x++)

        a[x] = 1;

    for (x=2; x < arraysize; x++)
    {
        if ( arraysize ==1)
        {
            while ( b < arraysize )
            {
        b = x;
                x = x + b;

            a[b] = 0;

            }
        }
    }

    a[1] = 0;
    cout << " here are your prime numbers from 1000 ";

    for (int c = 0; c < arraysize; c++)
    {
        if (a[c] = 1)
            cout << c << " ";
    }

    return 0;
Md Nayeem8y ago
Using the array i want to find out prime and factorial number in c program
Dharmraj Thakur8y ago
Please post what you did and where you are facing issue?
Ramesh Palanivel8y ago
Hi Md,

Please briefly explain your requirement. How you want to use array in those programes?