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local variable initialization were wrong java [closed]

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I am new to java, why a, b,c initialization are wrong in the following code.
public static void main(String[] args) {
if (args.length < 2)
throw new IllegalArgumentException ("we need 2 argumeents");
else {
int a = Integer.parseInt(args[0]);
int b = Integer.parseInt(args[1]);
int c = a+b;
}
System.out.println(a + " + " + b + " = " + c);
}

Java works differently compared to JavaScript. Every {} block has an own variable scope. Variables defined inside a block are not visible outside.
public static void main(String[] args) {
{
int x=1;
System.out.println(x); // prints 1
}
{
int x=2;
System.out.println(x); // prints 2
}
// System.out.println(x); // error: cannot find symbol
}

How do I retrieve the data input from a scanner to use in a method? [closed]

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Basically I have to write a program that uses data that was inputted by the user and put it in a mathematical formula so it spits out an answer. The formula has to be created as a method. This is what I have so far. When I run the code it lets me input a number, but when I do that the program does not output anything and it just finishes running.
import java.util.Scanner;
public class Namek {
static int myMethod(int radius) {
return ((radius * radius) * (22/7));
}
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter Radius");
String radius = keyboard.nextLine();
}
private static void myMethod() {
}

You need to call the method passing the radius as parameter of the method. You can check https://www.tutorialspoint.com/java/java_methods.htm
,this link to see how to create and call methods with parameters.
I think what you wanted to do is the following:
import java.util.*;
public class Namek {
static int myMethod(int radius) {
return ((radius * radius) * (22/7));
}
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter Radius");
int radius = Integer.valueOf(keyboard.nextLine());
int area = myMethod(radius);
System.out.println(area);
}
}

Below is what you were trying to do I think
public class Formula {
static int myMethod(int radius) {
return ((radius * radius) * (22/7));
}
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter Radius");
int radius = Integer.valueOf(keyboard.nextLine());
float output = myMethod(radius);
System.out.println(output);
}
}

C to Java (binary numbers programm) [closed]

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I made this program on C,and I have no idea of Java (new-yοung developer).Can you help me to "translate" it on Java?
#include<stdio.h>
#include<stdlib.h>
#include<graphics.h>
void printbin(int num)
{
int binnum;
binnum=num%2;
num=num/2;
if (num!=0) printbin(num);
printf("%d",binnum);
return;
system("pause");
}
int main(void)
{
int posnumber,binnum;
printf("Give a number : ");
scanf("%d",&posnumber);
printbin(posnumber);
printf("\n");
return 0;
}

You can learn from this code, hope this can help you:
//here is comments in java
package help;
import java.util.Scanner;
//this is the way how you can all the libraries in java so
/*
#include<stdio.h>
#include<stdlib.h>
#include<graphics.h>
*/
//here name of your class
public class Help {
//here name of your methode
public static void printbin(int num) {
int binnum;
binnum = num % 2;
num = num / 2;
if (num != 0) {
printbin(num);
}
System.out.println(binnum);
}
//here is the main methode in java
public static void main(String args[]) {
int posnumber, binnum;
Scanner scan = new Scanner(System.in);
System.out.println("Give a number : ");
posnumber = scan.nextInt();
System.out.println(posnumber);
}
}
Good luck, and good start with java :)

how do i print out the age multiplied by 3 [closed]

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I want the age to be multiplied by 3 here is my code asking for the user to enter name and age...............................................
import java.util.Scanner;
class Lab1Part4 {
public static void main (String [] args) {
Scanner user_input =
int tripleAge;
String printMyName;
String firstName;
String secondName;
System.out.println("Please enter your first name ? ");
firstName = user_input.next ();
System.out.println("Please enter your second name? ");
secondName = user_input.next ();
printMyName = firstName + " " + secondName;
System.out.println( printMyName);
System.out.println("Enter your age ? ");
tripleAge = user_input.nextInt ();
}// end class
}// end main

You just need to do something like:
tripleAge = user_input.nextInt () * 3;
System.out.println(tripleAge);

Use * operator to multiply.
tripleAge = (user_input.nextInt () * 3);
System.out.println(tripleAge);

java if nested loop [closed]

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Closed 8 years ago.
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It gives me following error: The operator == is undefined for the argument type(s)
boolean, int
Syntax error on tokens, delete these tokens
package javaproject;
public class NestedIFandIFandElse {
public static void main(String[] args) {
int vanus = 50;
if (vanus == 40) {
System.out.println("first if ");
} else {
System.out.print("first else");
if (vanus == 50 ∣∣ vanus == 20) {
System.out.println("second if");
} else {
System.out.println("second else");
}
}
}
}

You should change ∣∣ to ||. They look the same, but they aren't:
if (vanus == 50 || vanus == 20)

I'm not certain how you entered that symbol, but ∣∣ is not ||;
if (vanus == 50 || vanus == 20 ) { // <-- The || or works here.
I changed it as above, and it compiles here.