# [ Java ][HackerRank] 30 Days of code Day 1

## Day1-1. Hello World

``````import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class Solution {
public static void main(String[] args) {
// Create a Scanner object to read input from stdin.
Scanner scan = new Scanner(System.in);

// Read a full line of input from stdin and save it to our variable, inputString.
String inputString = scan.nextLine();
// Close the scanner object, because we've finished reading
// all of the input from stdin needed for this challenge.
scan.close();

// Print a string literal saying "Hello, World." to stdout.
System.out.println("Hello, World.");

// TODO: Write a line of code here that prints the contents of inputString to stdout.

System.out.println(inputString);

}
}
``````

## Day1-2. Data types

``````import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

public static void main(String[] args) {
int i = 4;
double d = 4.0;
String s = "HackerRank ";

Scanner scan = new Scanner(System.in);

/* Declare second integer, double, and String variables. */
int i2 = scan.nextInt();
double d2 = scan.nextDouble();
String s2 =scan.next() + scan.nextLine();

int sum = i + i2;
double sumd = d + d2;
String con = s.concat(s2);

System.out.println(sum);
System.out.printf("%.1f \n",sumd);
System.out.println(con);
/* Read and save an integer, double, and String to your variables.*/
// Note: If you have trouble reading the entire String, please go back and review the Tutorial closely.

/* Print the sum of both integer variables on a new line. */
// System.out.println(i + secondInt);
/* Print the sum of the double variables on a new line. */
// System.out.println(d + secondDouble);
/* Concatenate and print the String variables on a new line;
the 's' variable above should be printed first. */
// System.out.println(s + secondString);

scan.close();
``````

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