## Java programming Example

Question-1.

#### Write a program using a switch case to find the factor and factorial of a given number.

If the choice is 1 find Factor and 2 find Factorial of the input number.
Solution:
import java.util.*;
{
void main()
{
int ch,f,i,n;
Scanner sc=new Scanner(System.in);
System.out.println("1. Factor 2. Factorial:");
ch=sc.nextInt();
switch(ch)
{
case 1:
System.out.println("Enter a number to print Factor:");
n=sc.nextInt();
for(i=1;i<=n;i++)
{
if(n%i==0)
{
System.out.print(i+" ");
}
}
break;
case 2:
System.out.println("Enter a number to print Factorial:");
n=sc.nextInt();
f=1;
for(i=1;i<=n;i++)
{
f=f*i;
}
System.out.println("Factorial="+f);
break;
default:
System.out.println("Wrong Choice");
}
}
}
Question-2.

#### Write a program to print the following pattern up to n lines.

A
AB
ABC
ABCD
Upto n number[1>=n<=26]
Solution:
import java.util.*;
public class LetterPattern
{
void main()
{
int i,n,j;
Scanner sc=new Scanner(System.in);
System.out.println("Enter number 1-26 only");
n=sc.nextInt();
if(n>=1 && n<=26)
{
for(i=1;i<=n;i++)
{
for(j=65;j<=64+i;j++)
{
System.out.print((char)j);
}
System.out.println();
}
}
else
{
System.out.println("Pattern will not print");
}
}
}
Question-3.

### Write a program to print the Fibonacci series up to n term.

Solution:
import java.util.*;
public class Fibonacci
{
void main()
{
int f1,f2,fib,i,n;
Scanner sc=new Scanner(System.in);
System.out.println("Enter a number:");
n=sc.nextInt();
f1=fib=0;
f2=1;
for(i=0;i<n;i++)
{
f1=f2;
f2=fib;
fib=f1+f2;
System.out.print(fib+" ");
}
}
}
Question-4.

### Write a program to input a number and find whether it is a Neon Number or not.

A number is said to be a Neon Number. If it is equal to sum of digits of Square number.
92-> 81->8+1=9
Solution:
import java.util.*;
public class NeonNumber
{
void main()
{
int n,m,a,s=0;
Scanner sc=new Scanner(System.in);
System.out.println("Enter a number:");
n=sc.nextInt();
m=n*n;
while(m!=0)
{
a=m%10;
s=s+a;
m=m/10;
}
if(s==n)
System.out.println("It is a Neon Number");
else
System.out.println("It is not a Neon Number");
}

}

### Menu driven program in java with do-while loop

import java.util.*;
{
{
System.out.println("1. For Prime Number");
System.out.println("2. For Sum of digits of a Givem number");
System.out.println("3. For Factorial of a number");
System.out.println("4. For Exit------->");
}
public static void main(String args[])
{
// Local variables
int ch, num, m, sum=0, f, i, key=0;
Scanner sc=new Scanner(System.in);
// Do loop started
do{
ch=sc.nextInt();
System.out.println("Enter a number:");
num=sc.nextInt();
switch(ch)
{
case 1:
f=1;
for(i=2;i<num;i++)
{
if(num%i==0)
{
f=0; //Flag Variable
break;
}
}
if(f==1)
System.out.println("Prime Number");
else
System.out.println("Not Prime Number");
System.out.println("Press any key to continue");
key=sc.nextInt();
System.out.println("\f"); // form feed escap sequence
break;
case 2:
while(num!=0)
{
m=num%10;
sum=sum+m;
num=num/10;
}
System.out.println("Sum="+sum);
System.out.println("Press (0-9) key to continue");
key=sc.nextInt();
System.out.println("\f");
break;
case 3:
f=1;
for(i=1; i<=num; i++)
{
f=f*i;
}
System.out.println("Factorial="+f);
System.out.println("Press (0-9) key to continue");
key=sc.nextInt();
System.out.println("\f");
break;
case 4:
System.exit(0);
default:
System.out.println("Wrong Choice");
System.out.println("Press (0-9) key to continue");
key=sc.nextInt();
System.out.println("\f");
}
}while(ch != 4);
}
}