How to add first digit and last digit of three digit number using Java

By Ginna Srilekha

Basically we will be learning how to add first digit and last digit of three digit number using java.

How To Add First Digit and Last Digit of three Digit Number Using Java:

Initially we should take a 3 digit number.We can use Scanner class of util package to take user input.

After taking 3 digit number from user, we should save that number in a variable n. Take another variable num and save the contents of n in num.

Now To get first digit ,we should divide the number by 100.

For example: If we take 3 digit number as 645 ,To get first digit we should divide the number by 100( 645/100=>6).

To get first digit,as we have to divide the number by 100,first take a while loop and run the loop until the number becomes 0.We are using the while loop,to get the count of 3 digit number.As loop runs ,count becomes 3.

Now we are taking another for loop and a variable r which is initialized to 1.As the for loop runs,the value of r becomes 1000 as count =3.

Now we should divide 645/100. so that we get first digit 6. save this number in d variable. To get last digit, get the remainder(n%10) and save in re variable.

Take another variable sum and add d and re.

print sum.

class ad
{
  public static void main(String args[])
  {
    int count=0, r=1 ,d,sum=0,re,num;
    Scanner s=new Scanner(System.in);
    System.out.println("Enter three digit number:");
    int n=s.nextInt();
    num=n;
    while(num!=0)
    {
      num=num/10;
      count++;
    }
    for(int i=1;i<count;i++)
    {
      r=r*10;
    }
    d=n/r;
    re=n%10;
    sum=d+re;
    System.out.println("Sum="+sum);	
    
    
  }
}

 

Output:

Enter three digit number:
645
Sum=11