#include <stdio.h>
void main()
{
	char ch;
	int n,n1,n2,f,s,t,i,junk;
	clrscr();

	while(ch!='/')
	{
		printf("\nEnter Your Choice");
		printf("\n1. Even or odd");
		printf("\n2. Factorial");
		printf("\n3. Fibonacci");
		printf("\n4. Prime Number\n\t\t\t\t\tPress / to quit\n\tEnter your choice here:");
		scanf("%c",&ch);
		switch (ch)
		{
			case '1':printf("\nEnter the number: ");
						scanf("%d",&n);
						if(n%2==0)
						printf("\n\t\t\t**%d is even**\n",n);
						else
						printf("\n\t\t\t**odd**\n");
						break;
			case '2':printf("\nEnter a number: ");
						scanf("%d",&n);
						for (n1=f=1;n1<=n ;n1++)
						{
							f=f*n1;
						}
						printf("\n\t\t\t**Factorial of %d is %d**\n",n,f);
						break;
			case '3':printf("\nEnter the number for the Fabonacii series: ");
						scanf("%d",&n);
						f=0,s=1;n=n-2;
						printf("\n%d\n%d",f,s);
						while (n>0)
						{
							t=f+s;
							printf("\n%d",t);
							f=s,s=t,n--;
						}
						printf("\n");
						break;
			case '4':	printf("\nEnter a number: ");
							scanf("%d",&n);
							i=2;
							if(n==2)
								printf("\n\t\t\t**Not prime**\n");
							else if(n==1)
								printf("\n\t\t\t**Prime**\n");
							else
							{
								while (i<=n-1)
								{
									if(n%i==0)
									{
										printf("\n\t\t\t**Not Prime**\n");
										break;
									}//if
									i++;
								}//while
							if(i==n)
							printf("\n\t\t\t**Prime**\n");
							}//else
							break;
			case '/':break;
			default:printf("\n************************************");
					printf("\n!!!Invalid choice press / to quit!!!");
					printf("\n************************************\n");
		}//switch
	scanf("%c",&junk);
	}//while
	getch();
}