How do you find in java the sum of the first and last digit of 3 digit number?

Answer 1

String num = Integer.toString(12345); // Insert your Integer here.

int sum = 0;

for(int i = 0; i < num.length(); i++){

sum += Character.digit(num.charAt(i), 10);

}

System.out.println(sum); // Simply prints the sum of the digits to standard out.

///// ALTERNATE SOLUTION:

int num = 12345; // Insert your Integer here.

int sum = 0;

while (num > 0){

sum += num % 10;

num /= 10;

}

System.out.println(sum); // Simply prints the sum of the digits to standard out.

Answer 2

public SumRevInt(String args) {

System.out.println("in constr");

if(args == null)

{

System.out.println("hello, enter a choice during execution");

}

else

{

char[] ch = args.toCharArray();

System.out.println("add(digits)="+add(ch));

System.out.println("rev(digits)="+rev(ch));

}

}

static int add(char[] num)

{

int t=0;

for(int i=0;i<num.length;i++)

{

t += Integer.parseInt(String.valueOf(num[i]));

}

return t;

}

static int rev(char[] num)

{

String s = "";

for(int i=num.length-1;i>=0;i++)

{

s += String.valueOf(num[i]);

}

return Integer.parseInt(s);

}

public static void main(String[] args) {

myObj = new SumRevInt(args[0]);

}

Answer 3

import java.io.*;

class sumo

{

protected static void main()throws IOException

{

BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

System.out.print("Enter the Number: ");

int a=Integer.parseInt(in.readLine()),b=0;

for(int i=a;i>0;i/=10)

{

int c=i%10;

b+=c;

}

System.out.print("Sum= "+b);

}

}

Answer 4

The StringBuffer class has a method that does just that - you must simply convert your number to a StringBuffer object.

If you are supposed to program the loop yourself (this would be common for a study asignment), convert to String, then print out the digits one by one, in reverse order, using a forloop.

Answer 5

public static void main(String[ ] args)

{

int 3digit_num; // Assuming it is a three digit number

int sum_of_first_n_last_digit = (3digit_num/100) + (3digit_num%100)

System.out.println(sum_of_first_n_last_digit);

}

Answer 6

int middleDigit(final int n) { return (n/10) % 10;