Java Programming Tutorial – 7 – Building a Basic Calculator

Tip u can also type syso ctrl+space and then enter 🙂

WOW! This is a great video tutorial. Absolutely fantastic!

I love your vidoes man. Helping me pass my exams. You are more inspering then my teachers! Keep up the good work:D

For me it doesnt work with decimal numbers…only whole numbers…can anone help?

I get this error when I try and run the program: Exception in thread "main" java.lang.IllegalStateException: Scanner closed
at java.util.Scanner.ensureOpen(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextDouble(Unknown Source)
at bucky.applesnotfail.main(applesnotfail.java:11)
Here is the program i had:
package bucky;

import java.util.Scanner;

public class applesnotfail {
public static void main(String args[]){
Scanner bucky = new Scanner(System.in);
bucky.close();
double fnum, snum, answer;
System.out.println("Enter first num: ");
fnum = bucky.nextDouble();
System.out.println("Enter second num:");
snum = bucky.nextDouble();
answer = fnum + snum;
System.out.println(answer);
}

}

Please can someone help me in the last tutorial I had a problem running it as well and I think it is because of the import.java.util.Scanner; If I don’t put the package bucky; I get an error as well, same with when I move it to a different line. I don’t know what to do

This tutorial is almost 8 years old, but still the best one on youtube 🙂

I’m brand new at programming java and I managed to make a better calculator just after watching this. It’s just a couple extra System.Out statements but I think it’s pretty cool I found this out by my self.

package bucky;
import java.util.Scanner;

public class UserInput {
public static void main (String[] args) {
Scanner bucky = new Scanner(System.in);
double fnum, snum, answer;
System.out.println("Enter first Number");
fnum = bucky.nextDouble();
System.out.println("Enter second Number");
snum = bucky.nextDouble();
System.out.print(fnum);
System.out.print(" + ");
System.out.print(snum);
answer = fnum + snum;
System.out.print(" = ");
System.out.println(answer);

bucky.close();

}

}

Thanks a ton Bro! 🙂

import java.util.Scanner;
public class PracticeMethod {

public static void main(String[] args) {
Scanner in = new Scanner(System.in);

System.out.print("Enter your first Integer: ");
int Fnumber = in.nextInt();

System.out.print("Enter your second Integer: ");
int Snumber = in.nextInt();

int Result = Fnumber + Snumber;
System.out.println(Fnumber +" + "+ Snumber +" = "+ Result);

Result = Fnumber – Snumber;
System.out.println(Fnumber +" – "+ Snumber +" = "+ Result);

Result = Fnumber * Snumber;
System.out.println(Fnumber +" * "+ Snumber +" = "+ Result);

Result = Fnumber / Snumber;
System.out.println(Fnumber +" / "+ Snumber +" = "+ Result);

Result = Fnumber % Snumber;
System.out.println(Fnumber +" % "+ Snumber +" = "+ Result);

So the .nextDouble() method is saying to print the next variable on the next line? Bit confused on the exactly what the method is defining.

i learn so much about java programming on my campus but I’m not make that basic calculator before. this video improve my skills

Getting a "Resource leak: ‘scannername’ is never closed
Any fixes for this?
Thanks in advance

I love how the views are steadily decreasing with each video lmao

package PoopPackage1;
//[Made by Nic];
import java.util.Scanner;
import java.util.*;
public class Swqdfqewfqef {

public static final double number = 23.4333111;

private String name;
private int weight;
private boolean hasOwner = false;
private byte age;
private long uniqueID;
private char favoriteChar;
private double speed;
private float height;

protected static int numberOfAnimals = 0;

static Scanner userInput = new Scanner(System.in);

public Swqdfqewfqef() {
numberOfAnimals++;

int sumOfNumbers = 5 – 1;
System.out.println("5 – 1 = " + sumOfNumbers);

int diffOfNumbers = 5 + 1;
System.out.println("5 + 1 = " + diffOfNumbers);

int multOfNumbers = 5 * 1;
System.out.println("5 * 1 = " + multOfNumbers);

int divOfNumbers = 5 / 1;
System.out.println("5 / 1 = " + divOfNumbers);

int modOfNumbers = 5 % 3;
System.out.println("5 % 3 = " + modOfNumbers);
System.out.println("Enter the name: n");

//hasNextInt, hasNextFloat, hasNextDouble
//hasNextByte
//nextInt, nextFloat, nextdouble
if(userInput.hasNextLine()){
this.setName(userInput.nextLine());
}
this.setFavoriteColor();
this.setUniqueID();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getWeight() {
return weight;
}
public void setWeight(int weight) {
this.weight = weight;
}
public boolean isHasOwner() {
return hasOwner;
}
public void setHasOwner(boolean hasOwner) {
this.hasOwner = hasOwner;
}
public byte getAge() {
return age;
}
public void setAge(byte age) {
this.age = age;
}
public long getUniqueID() {
return uniqueID;
}
public void setUniqueID(long uniqueID) {
this.uniqueID = uniqueID;
System.out.println("Unique ID set tp: " + this.uniqueID);
}
public void setUniqueID() {
long minNumber = 1;
long maxNumber = 1000000;

this.uniqueID = minNumber + (long) (Math.random() *((maxNumber – minNumber) + 1));
String stringNumber = Long.toString(maxNumber);
int numberString = Integer.parseInt(stringNumber);
System.out.println("Unique ID set tp: " + this.uniqueID);
}
public char getFavoriteChar() {
return favoriteChar;
}
public void setFavoriteChar(char favoriteChar) {
this.favoriteChar = favoriteChar;
}
public void setFavoriteChar() {
int randomNumber = (int) (Math.random() * 126) + 1;
this.favoriteChar = (char) randomNumber;
if(randomNumber == 32){
System.out.println("Favorite character set to Space");

}else if(randomNumber == 10){
System.out.println("Favorite character set to Newline");
}else {
System.out.println("Favorite character set to " + this.FavoriteChar);
}
if((randomNumber > 97) && (randomNumber < 122)){
System.out.println("Favorite character is a lowercase letter");

}
System.out.println("Favorite character is a lowercase");
}
public double getSpeed() {
return speed;
}
public void setSpeed(double speed) {
this.speed = speed;
}
public float getHeight() {
return height;
}
public void setHeight(float height) {
this.height = height;
}
public static void main(String[] args){
Swqdfqewfqef theSwqdfqewfqef = new Swqdfqewfqef();
}
}

Everytime when i enter a double it gives me this error:

"
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextDouble(Unknown Source)
at me.bryan.javatest.Bryan.calc(Bryan.java:16)
at me.bryan.javatest.Main.main(Main.java:8)
"

When i input an integer the calculator works fine.

This is my code:

"
public void calc() {

Scanner input = new Scanner(System.in);
//
double numOne;
double numTwo;
double answer;
//
System.out.print("Enter your first number: ");
numOne = input.nextDouble();
//
System.out.print("Enter your second number: ");
numTwo = input.nextDouble();
//
answer = numOne + numTwo;
System.out.println("Your final answer is: " + answer);
}
}

"

import java.io.IOException;
import java.util.Scanner;

public class Claculator {

public static void main(String[] args) throws IOException{
char choice;
Scanner comu = new Scanner(System.in);

double first,second,answer;

System.out.println("Enter First Number " );
first = comu.nextDouble();

System.out.println("Enter Second Number");

second= comu.nextDouble();

System.out.println("please enter what operation you’d like");
System.out.println("1. ADD ");
System.out.println("2. SUBTRACT");
System.out.println("3. MULTIPLY");
System.out.println("4. DIVIDE");
System.out.println("5. GET REMAINDER");
choice = (char) System.in.read();
switch (choice){

case ‘1’:
answer = first+second;
System.out.println(answer);
break;
case’2′:
answer = first-second;
System.out.println(answer);
break;
case’3′:
answer = first*second;
System.out.println(answer);
break;
case ‘4’:
answer = first/second;
System.out.println(answer);
case ‘5’:
answer = first%second;
System.out.println(answer);
break;

}

}
}

what if you wanted to add a menu for that program how would you?

thanks you saved me

I am several tutorials farther but are there some practices I can do to help me memorize all of this stuff?

play the video at half speed…hilarious.

Great & Super Bro !! 😀

YOU’RE A LIFE SAVER. THANK YOU. I’M ACTUALLY UNDERSTANDING THIS. MY PROFESSOR IS ASIAN & I CAN’T UNDERSTAND HARDLY ANYTHING SHE SAYS WHICH MAKES MY PROGRAMMING 1 CLASS SO DIFFICULT BECAUSE I’M A BEGINNER. GOD BLESS YOU. I HAVE BEEN DELIVERT !!!!!

wow this is so much easier in c++

you are a great Teacher

Which software do you use for coding? ….. Cuz i ve got BlueJ.